Moving body

Abstract

To provide a moving body capable of improving aerodynamic drag-reduction effect in the moving body including the aerodynamic drag-reduction structure having a concave and convex structure.SOLUTION: A moving body is provided, the moving body 50 having an aerodynamic drag-reduction structure 1 on a surface thereof, in which the aerodynamic drag-reduction structure 1 has a first region having a concave and convex structure 10 and a second region adjacent to the first region, the first region and the second region extend in a band shape in a traveling direction of the moving body 50, a structure 20 is disposed on an outer periphery when the moving body 50 is viewed from the front, the aerodynamic drag-reduction structure 1 is disposed at a front portion of the structure 20 with reference to the traveling direction of the moving body 50, the aerodynamic drag-reduction structure 1 is disposed only after a position of the structure 20 with reference to the traveling direction of the moving body 50 on a surface on which the structure 20 is disposed, and height of the structure 20 is larger than boundary layer thickness of the moving body 50.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a moving body having a gas resistance reduction structure that reduces gas resistance. [Background technology]

[0002] In recent years, research into fluid resistance reduction technology has been actively conducted in order to achieve energy savings and reduced carbon dioxide emissions in the fields of moving objects that move through fluids and fluid transport, etc. Specifically, in the field of moving objects such as automobiles, railway vehicles, and aircraft, research into fluid resistance reduction technology has been actively conducted in order to achieve improved fuel efficiency and reduced carbon dioxide emissions.

[0003] Conventionally, known techniques for reducing fluid resistance include providing irregularities on the surface of an object. For example, riblets are known as a method for reducing frictional resistance, and dimples are known as a method for reducing pressure resistance (see, for example, Patent Document 1). Furthermore, Patent Document 2 discloses a technical concept of arranging rough and smooth surfaces to generate longitudinal vortices at the boundary between the rough and smooth surfaces, thereby suppressing flow separation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2010 / 29844 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-57390 [Patent Document 3] International Publication No. 2022 / 260181 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors of the present disclosure have devised a moving body equipped with an air resistance reduction structure having a concave-convex structure, which utilizes a technology for suppressing flow separation by generating vortices at the boundary between a rough surface and a smooth surface, as described in Patent Document 3. However, for practical use, further improvement in the air resistance reduction effect is desired.

[0006] The present disclosure has been made in consideration of the above-described situation, and aims to provide a moving body that is equipped with a gas resistance reduction structure having a concave-convex structure and that is capable of improving the gas resistance reduction effect. [Means for solving the problem]

[0007] One embodiment of the present disclosure provides a moving body having a gas resistance reduction structure on its surface, wherein the gas resistance reduction structure has a first region having a concave-convex structure and a second region adjacent to the first region, the first region and the second region extending in a band shape in the direction of travel of the moving body, a structure is arranged on the outer periphery of the moving body when viewed from the front, the gas resistance reduction structure is arranged in front of the structure with respect to the direction of travel of the moving body, the gas resistance reduction structure is arranged only after the position of the structure on the surface on which the structure is arranged with respect to the direction of travel of the moving body, and the height of the structure is greater than the boundary layer thickness of the moving body. [Effects of the Invention]

[0008] The present disclosure provides an advantage that it is possible to improve the gas resistance reduction effect in a moving body that is provided with an gas resistance reduction structure having a concave-convex structure. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are schematic plan and cross-sectional views illustrating a gas drag reduction structure according to the present disclosure. [Figure 2] 1 is a schematic perspective view illustrating a gas drag reduction structure according to the present disclosure. FIG. [Figure 3]3A to 3C are schematic diagrams illustrating gas flows in a gas drag reduction structure according to the present disclosure. [Figure 4] 1A to 1C are a schematic perspective view, a front view, and a side view illustrating a moving body according to the present disclosure. [Figure 5] 1A and 1B are schematic side and front views illustrating a moving body according to the present disclosure. [Figure 6] 1A and 1B are schematic side and front views illustrating a moving body according to the present disclosure. [Figure 7] 1A and 1B are schematic side and front views illustrating a moving body according to the present disclosure. [Figure 8] 1A and 1B are schematic side and front views illustrating a moving body according to the present disclosure. [Figure 9] 1 is a schematic side view illustrating a structure and a gas drag reduction structure according to the present disclosure. FIG. [Figure 10] 3A to 3C are schematic diagrams illustrating gas flows in a gas resistance reduction structure. [Figure 11] 1 is a schematic cross-sectional view illustrating a gas drag reduction structure according to the present disclosure. [Figure 12] 1 is a schematic perspective view illustrating a gas drag reduction structure according to the present disclosure. FIG. [Figure 13] 1A and 1B are schematic plan and cross-sectional views illustrating a gas drag reduction structure according to the present disclosure. [Figure 14] 1A and 1B are schematic plan and cross-sectional views illustrating a gas drag reduction structure according to the present disclosure. [Figure 15] 1 is a schematic plan view illustrating a gas drag reduction structure according to the present disclosure. [Figure 16] 3 is a schematic cross-sectional view illustrating an example of the concave-convex structure of a first region of the gas drag reduction structure according to the present disclosure. FIG. [Figure 17] 3 is a schematic cross-sectional view illustrating an example of a convex portion in the concave-convex structure of a first region of the gas drag reduction structure according to the present disclosure. FIG. [Figure 18] 1 is a schematic plan view illustrating a gas drag reduction structure according to the present disclosure. [Figure 19] 1 is a schematic cross-sectional view illustrating an example of a concave-convex resin film having a gas resistance reducing structure according to the present disclosure. [Figure 20] 1 is a schematic cross-sectional view illustrating an example of a concave-convex resin film having a gas resistance reducing structure according to the present disclosure. [Figure 21] 1A to 1C are schematic top, side and rear views showing a truck-shaped model. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be implemented in many different forms and should not be construed as being limited to the description of the embodiments exemplified below. Furthermore, to clarify the explanation, the drawings may show the width, thickness, shape, etc. of each part schematically compared to the actual form, but these are merely examples and do not limit the interpretation of the present disclosure. Furthermore, in this specification and each drawing, elements similar to those described above with reference to the previous drawings may be designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0011] In this specification, when describing an aspect in which another component is disposed on a certain component, the term "above" or "below" includes, unless otherwise specified, both a case in which another component is disposed directly above or below a certain component so as to be in contact with the component, and a case in which another component is disposed above or below a certain component with another component interposed therebetween. Also, in this specification, when describing an aspect in which another component is disposed on the surface of a certain component, the term "on the surface" includes, unless otherwise specified, both a case in which another component is disposed directly above or below a certain component so as to be in contact with the component, and a case in which another component is disposed above or below a certain component with another component interposed therebetween.

[0012] The mobile body in this disclosure will be described in detail below.

[0013] The moving body in the present disclosure is a moving body having a gas resistance reduction structure on its surface, the gas resistance reduction structure having a first region having a concave-convex structure and a second region adjacent to the first region, the first region and the second region extending in a band shape in the direction of travel of the moving body, a structure is arranged on the outer periphery of the moving body when viewed from the front, the gas resistance reduction structure is arranged in front of the structure with respect to the direction of travel of the moving body, on the surface on which the structure is arranged, the gas resistance reduction structure is arranged only after the position of the structure with respect to the direction of travel of the moving body, and the height of the structure is greater than the boundary layer thickness of the moving body.

[0014] The present disclosure utilizes a technology that generates vortices at the boundary between a rough surface and a smooth surface to suppress flow separation. When gas flows along a rough surface and a smooth surface, the frictional resistance of the rough surface is greater than the frictional resistance of the smooth surface. Therefore, the gas flow velocity is faster on the smooth surface and slower on the rough surface, resulting in a difference in gas flow velocity between the smooth surface and the rough surface. As a result, vortices are generated at the boundary between the rough surface and the smooth surface. In the present disclosure, the first region has an uneven structure and is a region where the frictional resistance of the gas is high. On the other hand, the second region is a region where the frictional resistance of the gas is low. Therefore, when gas flows along the surface of the gas drag reduction structure, vortices are generated at the boundary between the first region and the second region.

[0015] As described above, the second region is a region in which the frictional resistance of the gas is smaller than that of the first region. The second region does not have a concave-convex structure and has a flat surface. Alternatively, the second region may have a concave-convex structure, in which case the height of the convex portions in the second region is smaller than the height of the convex portions in the first region.

[0016] 1(a) to 1(c) and 2 are schematic plan views, cross-sectional views, and perspective views showing an example of a gas drag reduction structure according to the present disclosure. FIG. 1(b) is a cross-sectional view taken along line AA in FIG. 1(a), FIG. 1(c) is a cross-sectional view taken along line BB in FIG. 1(a), and FIG. 2 is a perspective view of FIG. 1(a). As shown in FIGS. 1(a) to 1(c) and 2, in the gas drag reduction structure 1, a first region 2 having an uneven structure 10 including a plurality of protrusions 11 and recesses 12 and a second region 3 adjacent to the first region 2 extend in a strip-like shape in the traveling direction D1 of the moving object. In the example shown in FIGS. 1(a) to 1(c) and 2, the first regions 2 and the second regions 3 are alternately arranged in a direction D2 intersecting the traveling direction D1 of the moving object.

[0017] 3(a) and 3(b) are schematic diagrams illustrating the flow of gas in the gas resistance reduction structure of the present disclosure, and Fig. 3(b) is a cross-sectional view taken along line AA in Fig. 3(a). As shown in Fig. 3(a), when gas F flows along the surface of the gas resistance reduction structure 1, the flow direction d of the gas F between the first region 2 and the second region 3 is F A vortex V is generated near the boundary parallel to the first region. The generation of the vortex V can suppress the flow of gas F from separating from the surface of the gas drag reduction structure 1. When an object is placed in a gas flow, drag forces acting on the object include, for example, frictional resistance and pressure resistance. Frictional resistance is generated by friction between the gas and the surface. Pressure resistance is generated by the pressure difference between the front and rear. In other words, pressure resistance is generated by flow separation. In the gas drag reduction structure of the present disclosure, attention is focused on reducing pressure resistance, among other gas resistances. In the gas drag reduction structure of the present disclosure, flow separation can be suppressed by generating a vortex near the boundary between the first region and the second region, and gas resistance, particularly pressure resistance, can be reduced.

[0018] The inventors of the present disclosure have conducted extensive research to improve the gas resistance reduction effect of a moving body having a gas resistance reduction structure on its surface, and have found that arranging a gas resistance reduction structure at the front of the moving body relative to the moving direction of the moving body improves the gas resistance reduction effect. This is for the following reasons. First, the gas resistance reduction structure suppresses flow separation at the front of the moving body, thereby suppressing a decrease in gas flow velocity from the front to the rear of the moving body. As a result, more gas flows rearward of the moving body, increasing back pressure and reducing pressure drag. This improves the gas resistance reduction effect.

[0019] In moving bodies such as automobiles, railway vehicles, and aircraft, structures such as exterior parts are sometimes arranged on the outside of the moving body. As a result of further investigation, the inventors of the present disclosure have found new problems: when there is a structure between the front and rear of the moving body, even if a gas drag reduction structure is arranged at the front of the moving body, the structure may become an obstacle, resulting in an insufficient effect of suppressing a decrease in gas flow velocity between the front and rear of the moving body; and the gas drag reduction structure arranged at the front of the moving body may increase frictional resistance.

[0020] In a flow around an object, a very thin layer on the object's surface is strongly affected by viscosity. This layer that is strongly affected by viscosity is called a boundary layer. The inventors of the present disclosure conducted further research and found that when a structure is present between the front and rear of a moving object and the height of the structure is greater than the boundary layer thickness of the moving object, the structure acts as an obstacle, as described above, and the effect of suppressing the decrease in gas flow velocity between the front and rear of the moving object is insufficient. In other words, when the height of the structure is greater than the boundary layer thickness of the moving object, the gas flow hits the structure and slows down. On the other hand, when the height of the structure is smaller than the boundary layer thickness of the moving object, the gas flow is less likely to slow down compared to when the height of the structure is greater than the boundary layer thickness of the moving object.

[0021] The inventors of the present disclosure have found that when there is a structure between the front and rear of a moving body and the height of the structure is greater than the boundary layer thickness of the moving body, the gas drag reduction effect can be improved by arranging a gas drag reduction structure in front of the structure and not arranging a gas drag reduction structure ahead of the structure. The present disclosure is based on this finding.

[0022] 4(a) to 4(c) are schematic perspective views, front views, and side views showing an example of a mobile body according to the present disclosure, where the mobile body is a bus. As shown in FIGS. 4(a) to 4(c), a bus 50, which is a mobile body, is provided with an air conditioning unit 52 on top of a body 51. The air conditioning unit 52 is a structure 20 arranged on the periphery 21 of the bus 50 (mobile body) when viewed from the front. The height H10 of the air conditioning unit 52 (structure 20) is greater than the boundary layer thickness of the bus 50 (mobile body). Furthermore, an air drag reduction structure 1 is arranged in front of the air conditioning unit 52 (structure 20) with respect to the traveling direction D1 of the bus 50 (mobile body). In FIG. 4(b), the periphery 21 of the bus 50 (mobile body) when viewed from the front is indicated by a thick line.

[0023] On the surface of the bus 50 (mobile body) where the air conditioning unit 52 (structure 20) is located, i.e., on the top surface of the bus 50 (mobile body), the gas resistance reduction structure 1 is located only after the position of the air conditioning unit 52 (structure 20) with respect to the traveling direction D1 of the bus 50 (mobile body). In other words, on the top surface of the bus 50 (mobile body), the gas resistance reduction structure 1 is not located ahead of the air conditioning unit 52 (structure 20).

[0024] 4(a) to 4(c), in addition to the front of the air conditioning device 52 (structure 20), the gas drag reduction structure 1 is also arranged in a peripheral portion that is arranged on the periphery 21 when the bus 50 (mobile body) is viewed from the front, and in the front portion of the peripheral portion based on the traveling direction D1 of the bus 50 (mobile body). Specifically, the gas drag reduction structure 1 is arranged on the front side of the bus 50. On the side of the bus 50, the front side of the bus 50 is a peripheral portion that is arranged on the periphery 21 when the bus 50 (mobile body) is viewed from the front, and is the front portion of the peripheral portion.

[0025] In the present disclosure, when the height of a structure is greater than the boundary layer thickness of a moving body, a gas resistance reduction structure is disposed in front of the structure, thereby suppressing flow separation at the structure. Therefore, a decrease in gas flow velocity is suppressed between the structure and the rear of the moving body. As a result, more gas flows rearward of the moving body, increasing back pressure and reducing pressure drag. Furthermore, in the present disclosure, when the height of a structure is greater than the boundary layer thickness of a moving body and a gas resistance reduction structure is disposed in front of the structure, the gas resistance reduction structure is disposed only behind the structure on the surface on which the structure is disposed, relative to the traveling direction of the moving body. In other words, the gas resistance reduction structure is not disposed forward of the structure, thereby suppressing an increase in frictional resistance due to the gas resistance reduction structure. Therefore, the gas resistance reduction effect can be improved.

[0026] 5(a) and 5(b) are schematic side and front views showing an example of a mobile body according to the present disclosure, where the mobile body is a truck. As shown in FIGS. 5(a) and 5(b), the mobile body, truck 60, includes a cabin 61 and a bed 62. The bed 62 is a structure 20 disposed on the outer periphery 21 of the truck 60 (mobile body) when viewed from the front. A height H10 of the bed 62 (structure 20) is greater than the boundary layer thickness of the truck 60 (mobile body). Furthermore, a gas drag reduction structure 1 is disposed in front of the bed 62, with respect to the traveling direction D1 of the truck 60 (mobile body). In FIG. 5(b), the outer periphery 21 of the truck 60 (mobile body) when viewed from the front is indicated by a thick line.

[0027] On the surface of the truck 60 (mobile body) where the loading platform 62 (structure 20) is arranged, i.e., on the upper surface of the truck 60, the gas drag reduction structure 1 is arranged only after the position of the loading platform 62 (structure 20) with respect to the traveling direction D1 of the truck 60 (mobile body). In other words, on the upper surface of the truck 60, the gas drag reduction structure 1 is not arranged ahead of the loading platform 62 (structure 20).

[0028] 5(a) and 5(b), in addition to the front part of the loading platform 62 (structure 20), the gas resistance reduction structure 1 is also arranged in a peripheral portion that is arranged on the outer periphery 21 when the truck 60 (mobile body) is viewed from the front, and in the front part of the peripheral portion based on the traveling direction D1 of the truck 60 (mobile body). Specifically, the gas resistance reduction structure 1 is arranged on the front side of the cabin 61 and the front side of the loading platform 62. On the side of the truck 60, the front side of the cabin 61 and the front side of the loading platform 62 are peripheral portions that are arranged on the outer periphery 21 when the truck 60 (mobile body) is viewed from the front, and are the front parts of the peripheral portion.

[0029] In the example shown in FIG. 5, the gas resistance reduction effect can be improved, similarly to the example shown in FIG.

[0030] The mobile body in this disclosure will be described in detail below.

[0031] 1. Mobile The mobile body in the present disclosure is a mobile body that has a driver's seat and a windshield in front of the driver's seat. Examples of mobile bodies include automobiles such as passenger cars, trucks, and buses; railway vehicles such as trains, bullet trains, and locomotives; aircraft such as passenger planes, helicopters, and air mobility; and ships. Air mobility is what is known as a flying car. The mobile body is preferably a non-streamlined body, specifically a bluff body. This is because, in a bluff body, pressure resistance contributes significantly to gas resistance, and the effects of the present disclosure are particularly pronounced. Preferred examples of mobile bodies that are bluff bodies include trucks, buses, and the like.

[0032] 2.Structures In the present disclosure, structures are arranged on the outer periphery of a moving body when viewed from the front. The structures vary depending on the moving body. When the moving body is an automobile or a railroad vehicle, tall structures are rarely arranged on the side of the moving body in order to avoid contact between the moving bodies and between the moving body and people or objects, and structures are often arranged on the top surface of the moving body. In the case of a bus, examples of the structures include air conditioning units, aerodynamic parts, and steps. In the case of a truck, examples of the structures include aerodynamic parts such as a loading platform and air deflectors. In the case of a passenger car, examples of the structures include roof boxes, warning lights, company name signs, aerodynamic parts, and steps. In the case of a train or a bullet train, examples of the structures include air conditioning units and aerodynamic parts such as pantograph covers and pantograph soundproofing panels.

[0033] The height of a structure is greater than the boundary layer thickness of the moving body. The "height of a structure" refers to the amount of protrusion of the structure when viewed from the front of the moving body. Specifically, when a structure is placed on the top surface of a moving body, the "height of a structure" refers to the amount of protrusion of the structure in the vertical direction when viewed from the front of the moving body. Furthermore, when a structure is placed on the side of a moving body, the "height of a structure" refers to the amount of protrusion of the structure in the horizontal direction when viewed from the front of the moving body. More specifically, when a structure is placed on the top surface of a moving body, the "height of a structure" refers to the maximum height of the structure in the vertical direction. Furthermore, when a structure is placed on the side of a moving body, the "height of a structure" refers to the maximum width of the structure in the horizontal direction. Since structures are usually attached to the main body of a moving body, the boundary between the structure and the main body of the moving body is clear. Note that when the boundary between the structure and the main body of the moving body is unclear, the part where the shape begins to change is considered to be the boundary between the structure and the main body of the moving body.

[0034] However, if a part of the mobile body or another structure is adjacent to the front of the structure, and part of the structure overlaps with part of the mobile body or another structure when viewed from the front of the mobile body, the maximum vertical height or maximum horizontal width of the structure does not necessarily represent the protrusion amount of the structure. In such cases, the protrusion amount of the structure from the part adjacent to the front of the structure is considered to be the "height of the structure."

[0035] 4(a) to 4(c), the air conditioning unit 52 (structure 20) is disposed on the upper surface of the bus 50 (mobile body). The height of the air conditioning unit 52 (height H10 of the structure 20) is the amount of protrusion of the air conditioning unit 52 (structure 20) in the vertical direction, that is, the maximum height of the air conditioning unit 52 (structure 20) in the vertical direction.

[0036] In addition, in the bus 50 (mobile body) shown in Figures 6(a) and 6(b), the air conditioning unit 52 (structure 20) is disposed on the upper surface of the bus 50 (mobile body). The height of the air conditioning unit 52 (height H10 of the structure 20) is the amount of protrusion of the air conditioning unit 52 (structure 20) in the vertical direction, that is, the maximum height of the air conditioning unit 52 (structure 20) in the vertical direction. Note that in Figures 6(a) and 6(b), the front of the bus 50 (mobile body) and the upper surface of the air conditioning unit 52 (structure 20) are smoothly connected, but as described above, the boundary between the structure 20 and the main body of the mobile body is usually clear.

[0037] In the truck 60 (mobile body) shown in FIGS. 5(a) and 5(b), a loading platform 62 (structure 20) is disposed on the upper surface of the truck 60 (mobile body). The height of the loading platform 62 (height H10 of the structure 20) is the amount of protrusion of the loading platform 62 (structure 20) in the vertical direction. In this case, a cabin 61 (part of the mobile body body) is adjacent to the front of the loading platform 62 (structure 20), and when the truck 60 (mobile body) is viewed from the front, a part of the loading platform 62 (structure 20) overlaps with the cabin 61. Therefore, the amount of protrusion of the loading platform 62 (structure 20) from the part adjacent to the front of the loading platform 62 (structure 20) (the cabin 61 in FIG. 5(b)) is defined as the height of the loading platform 62 (height H10 of the structure 20).

[0038] In the truck 60 (mobile body) shown in FIGS. 7(a) and 7(b), a loading platform 62 (structure 20) is disposed on the upper surface of the truck 60 (mobile body). The height of the loading platform 62 (height H10 of the structure 20) is the amount of protrusion of the loading platform 62 (structure 20) in the vertical direction. In this case, a cabin 61 (part of the mobile body body) and an air deflector 63 (another structure) are adjacent to the front of the loading platform 62 (structure 20). When the truck 60 (mobile body) is viewed from the front, a part of the loading platform 62 (structure 20) overlaps with the cabin 61 and the air deflector 63. Therefore, the amount of protrusion of the loading platform 62 (structure 20) from the adjacent front part of the loading platform 62 (structure 20) (the air deflector 63 in FIG. 7(b)) is defined as the height of the loading platform 62 (height H10 of the structure 20).

[0039] 8(a) and 8(b), an air deflector 63 (structure 20) is disposed on the upper surface of the truck 60 (mobile body). The height of the air deflector 63 (height H10 of the structure 20) is the amount of protrusion of the air deflector 63 (structure 20) in the vertical direction, that is, the maximum height of the air deflector 63 (structure 20) in the vertical direction.

[0040] The boundary layer thickness δ of a moving body is calculated by the following formula (1). δ=0.37(v / U0x) 1 / 5 x (1) In the above formula (1), v represents the dynamic viscosity coefficient of the gas, U0 represents the gas flow velocity, and x represents the distance from the tip of the front window of the moving object to the tip of the structure. When the gas is air, the dynamic viscosity coefficient v of air at 20°C is 1.512×10 -5 m 2 / s.

[0041] The gas flow velocity U0 varies depending on the moving object. If there is a legal speed limit (legal maximum speed), the gas flow velocity is determined based on that limit. If there is no legal speed limit, the gas flow velocity is determined based on the maximum speed during normal movement.

[0042] When the moving body is a car, the gas flow velocity is determined based on the legal speed (maximum legal speed). The legal speed on ordinary roads is 60 km / h, and on expressways it is 100 km / h. Therefore, the gas flow velocity is set to 100 km / h. For automobiles such as large freight vehicles, the legal speed on expressways is 80 km / h, but when the moving body is a car, the gas flow velocity is set to 100 km / h.

[0043] When the moving object is a railway vehicle, the gas flow velocity is determined based on the maximum speed during normal operation. For railway vehicles, the maximum speed during normal operation is called the maximum operating speed or maximum line speed (maximum route speed). Maximum operating speed and maximum line speed vary depending on the vehicle and route. For the Shinkansen, the maximum operating speed is approximately 250 km / h to 320 km / h, so the gas flow velocity is set to 320 km / h. For linear motor cars, the maximum operating speed is planned to be 500 km / h, so the gas flow velocity is set to 500 km / h. For trains and locomotives other than the Shinkansen, the maximum operating speed is approximately 70 km / h to 110 km / h, so the gas flow velocity is set to 110 km / h.

[0044] When the moving object is an aircraft, the gas flow velocity is determined based on the maximum speed during normal flight. The economical and efficient speed at which an aircraft can travel as long a distance or for as long a time as possible with as little fuel consumption as possible is called the cruising speed. The cruising speed of a passenger plane is approximately 670 km / h to 900 km / h, so when the moving object is a passenger plane, the gas flow velocity is set to 900 km / h. The cruising speed of a helicopter is approximately 140 km / h to 240 km / h, so when the moving object is a helicopter, the gas flow velocity is set to 240 km / h. The cruising speed of air mobility is approximately 100 km / h to 160 km / h, so when the moving object is air mobility, the gas flow velocity is set to 160 km / h.

[0045] If the moving body is a ship, the gas flow velocity is determined based on the maximum speed during normal navigation. The cruising speed of a ship is approximately 30km / h to 45km / h, depending on the type of ship, so if the moving body is a ship, the gas flow velocity is set at 45km / h.

[0046] The distance x from the tip of the windshield of a moving body to the tip of a structure is the horizontal distance from the tip of the windshield of the moving body to the tip of the structure in the direction of travel of the moving body. The tip of the windshield of a moving body is the part of the windshield that is located foremost relative to the direction of travel of the moving body. The tip of a structure is the part of the structure that is located foremost relative to the direction of travel of the moving body.

[0047] In Figure 4(c), the distance x is the distance from the tip E1 of the front window 53 of the bus 50 (mobile body) to the tip E2 of the air conditioning unit 52 (structure 20) in the traveling direction D1 of the bus 50 (mobile body). Also, in Figure 5(c), the distance x is the distance from the tip E1 of the front window 64 of the truck 60 (mobile body) to the tip E2 of the cargo bed 62 (structure 20) in the traveling direction D1 of the truck 60 (mobile body).

[0048] The gas drag reduction structure is disposed at the front of the structure, with the direction of travel of the moving body as the reference. The structure is disposed on the outer periphery of the moving body when viewed from the front, and the front of the structure is the part that is hit by the gas flow as the moving body travels. Therefore, flow separation is likely to occur at the front of the structure. It is sufficient that the gas drag reduction structure is disposed in at least a part of the front of the structure.

[0049] To reduce gas resistance, the corners of a moving body, which are the boundaries between the front and top surfaces of the moving body, the corners of the boundaries between the front and side surfaces of the moving body, and the corners of the boundaries between the front and bottom surfaces of the moving body, are often rounded. Similarly, to reduce gas resistance, the corners of a structure, which are the boundaries between the front and top surfaces of the structure, the corners of the boundaries between the front and side surfaces of the structure, and the corners of the boundaries between the front and bottom surfaces of the structure, are often rounded. In this case, as shown in FIGS. 9(a) to 9(c), for example, a structure 20 has, from the top surface of the structure 20 toward the front, a flat portion 22 and a curved portion 23 located in front of and connected to the flat portion 22. Similarly, the structure has, from the side surfaces of the structure toward the front, a flat portion and a curved portion located in front of and connected to the flat portion.

[0050] When the gas drag reduction structure is placed at the front of the structure based on the direction of travel of the moving body, the gas drag reduction structure 1 may be placed across the flat portion 22 and the curved portion 23 of the structure 20, as illustrated in Figure 9(a), the gas drag reduction structure 1 may be placed only on the flat portion 22 of the structure 20, as illustrated in Figure 9(b), or the gas drag reduction structure 1 may be placed only on the curved portion 23 of the structure 20, as illustrated in Figure 9(c).

[0051] Furthermore, flow separation is more likely to occur near the point where the radius of curvature changes at the front of the structure. Therefore, among the above, as exemplified in Figures 9(a) and 9(c), it is preferable that the gas drag reduction structure 1 is disposed at least at the curved portion 23 of the structure 20 at the front of the structure 20. In other words, it is preferable that the gas drag reduction structure is disposed so as to straddle the point where the radius of curvature changes at the front of the structure. By disposing the gas drag reduction structure in this manner, flow separation can be effectively suppressed.

[0052] The gas drag reduction structure is disposed only after the position of the structure on the surface on which the structure is disposed, with the traveling direction of the moving body as the reference. On the surface on which the structure is disposed, the "position of the structure" in "after the position of the structure" refers to the position of the tip of the structure, with the traveling direction of the moving body as the reference.

[0053] 4(a) to 4(c) and 6(a) to 6(b), on the surface on which the air conditioning unit 52 (structure 20) is arranged, i.e., on the top surface of the bus 50 (mobile body), the gas resistance reduction structure 1 is arranged only after the position of the tip E2 of the air conditioning unit 52 (structure 20) with respect to the traveling direction D1 of the bus 50 (mobile body). In other words, on the surface on which the air conditioning unit 52 (structure 20) is arranged, i.e., on the top surface of the bus 50 (mobile body), the gas resistance reduction structure 1 is not arranged ahead of the air conditioning unit 52 (structure 20).

[0054] 5(a) to 5(b) and 7(a) to 7(b), on the surface on which the loading platform 62 (structure 20) is arranged, i.e., on the upper surface of the truck 60 (mobile body), the gas drag reduction structure 1 is arranged only after the position of the tip E2 of the loading platform 62 (structure 20) with respect to the traveling direction D1 of the truck 60 (mobile body). In other words, on the surface on which the loading platform 62 (structure 20) is arranged, i.e., on the upper surface of the truck 60 (mobile body), the gas drag reduction structure 1 is not arranged forward of the loading platform 62 (structure 20).

[0055] 8(a) and 8(b), on the surface on which the air deflector 63 (structure 20) is arranged, i.e., on the upper surface of the truck 60 (mobile body), the gas drag reduction structure 1 is arranged only behind the position of the tip E2 of the air deflector 63 (structure 20) with respect to the traveling direction D1 of the truck 60 (mobile body). In other words, on the surface on which the air deflector 63 (structure 20) is arranged, i.e., on the upper surface of the truck 60 (mobile body), the gas drag reduction structure 1 is not arranged ahead of the air deflector 63 (structure 20).

[0056] The "direction of travel of a moving body" refers to the direction in which gas moves along the surface of the moving body as the moving body moves. For example, if the moving body is an automobile or a railroad vehicle, the moving body can move forward, backward, turn right, turn left, etc., and in this case, the direction of travel of the moving body refers to the direction in which the moving body moves forward. Also, for example, if the moving body is an aircraft, the direction of travel of the moving body refers to the direction in which the moving body moves during flight.

[0057] 3. Gas Drag Reduction Structure The gas drag reduction structure according to the present disclosure has a first region having a concave-convex structure and a second region adjacent to the first region, and the first region and the second region extend in a band shape in the traveling direction of the moving body.

[0058] (1) First area In the present disclosure, the first region has a concave-convex structure.

[0059] In the gas drag reduction structure of the present disclosure, it is preferable that the height H1 of the convex portions 11 of the concave-convex structure 10 be within a predetermined range.

[0060] As mentioned above, when an object is placed in a gas flow, the drag forces acting on the object include, for example, frictional resistance and pressure resistance, with pressure resistance occurring due to flow separation. Pressure resistance is a problem for moving objects such as automobiles, trains, and airplanes. The flow speed of gas flowing through such moving objects is, for example, between 10 km / h and 900 km / h.

[0061] In the gas resistance reduction structure of the present disclosure, when the flow velocity of the gas flowing through the moving body is within the above range, by appropriately adjusting the height H1 of the convex portions 11 within a predetermined range, it is possible to make it easier for vortices V to be generated near the boundary between the first region 2 and the second region 3. This makes it possible to suppress separation of the flow from the surface of the gas resistance reduction structure and reduce pressure resistance.

[0062] The height of the convex portions is preferably, for example, 1.1 μm or more, preferably 10 μm or more, more preferably 20 μm or more, and even more preferably 50 μm or more. On the other hand, the height of the convex portions is, for example, preferably 1000 μm or less, more preferably 800 μm or less, even more preferably 500 μm or less, and particularly preferably 200 μm or less. Specifically, the height of the convex portions is preferably 1.1 μm or more and 1000 μm or less, preferably 10 μm or more and 1000 μm or less, more preferably 15 μm or more and 800 μm or less, more preferably 20 μm or more and 500 μm or less, particularly preferably 20 μm or more and 200 μm or less, and most preferably 50 μm or more and 200 μm or less. As mentioned above, the flow rate of gas flowing in moving bodies such as automobiles, trains, and airplanes is approximately 10 km / h or more and 900 km / h or less. When the flow velocity is within the above range, adjusting the height of the convex portion appropriately within the above range can facilitate the generation of vortices near the boundary between the first and second regions. For example, the speed of a vehicle is approximately 10 km / h or more and 120 km / h or less, and in this case, the flow velocity of the air flowing through the vehicle is approximately 10 km / h or more and 120 km / h or less. When the flow velocity is within the above range, adjusting the height of the convex portion appropriately within the range of 20 μm or more and 500 μm or less can facilitate the generation of vortices near the boundary between the first and second regions. Furthermore, by keeping the height of the convex portion within the above range, the benefit of reduced pressure resistance can be greater than the increase in frictional resistance due to the first region.

[0063] As mentioned above, in a flow around an object, a very thin layer on the object's surface is strongly affected by viscosity. This layer that is strongly affected by viscosity is called the boundary layer. The height of the convex portion is preferably between 1 / 100 and 1 / 10 of the boundary layer thickness. Furthermore, since the boundary layer thickness becomes thinner as the gas flow velocity increases, the height of the convex portion is preferably lower within the above range as the gas flow velocity increases.

[0064] The height H1 of the convex portion 11 refers to the height from the bottom of the recess 12 in the concave-convex structure 10 in the first region 2 to the top of the convex portion 11, as shown in FIG. 1(c), for example. Specifically, as will be described later, when a convex portion in the first region protrudes relative to the surface of the second region, the height of the convex portion refers to the height from the bottom of the recess located between two adjacent convex portions to the top of the convex portion. Furthermore, as will be described later, when a recess in the first region is recessed relative to the surface of the second region, the height of the convex portion refers to the height from the bottom of the recess to the top of the convex portion located between two adjacent recesses.

[0065] In the gas drag reduction structure of the present disclosure, it is preferable that the width W1 of the first region 2 in the direction D2 intersecting the traveling direction of the moving body be within a predetermined range.

[0066] As mentioned above, in the flow around an object, a very thin layer on the surface of the object is strongly affected by viscosity. This layer that is strongly affected by viscosity is called the boundary layer.

[0067] 10(a) to 10(c) are schematic diagrams illustrating the relationship between the widths of the first and second regions in a direction intersecting the direction of travel of the moving body and the vortices generated near the boundary between the first and second regions in a gas drag reduction structure. In FIGS. 10(a) to 10(c), δ represents the boundary layer thickness. For example, as shown in FIG. 10(a), when the width W1 of the first region 2 and the width W2 of the second region 3 in a direction intersecting the direction of travel of the moving body are large, a large vortex V is generated near the boundary between the first and second regions 2 and 3, but the vortex V does not easily reach the center of the first region 2 and the center of the second region 3. Also, as shown in FIG. 10(c), when the width W1 of the first region 2 and the width W2 of the second region 3 in a direction intersecting the direction of travel of the moving body are small, the vortex V generated near the boundary between the first and second regions 2 and 3 is small, and the vortex V does not easily reach the outer edge of the boundary layer. In these cases, flow separation can be suppressed, but the effect is limited.

[0068] In contrast, by setting the width W1 of the first region 2 and the width W2 of the second region 3 in the direction D2 intersecting the direction of travel of the moving body within a predetermined range, a large vortex V is generated near the boundary between the first region 2 and the second region 3, as shown in Figure 10(b), for example, and the vortex V can be generated throughout the entire boundary layer.

[0069] The width of the first region in the direction intersecting the traveling direction of the moving body is preferably, for example, 0.2 mm or more, and more preferably 1 mm or more. On the other hand, the width of the first region in the direction intersecting the traveling direction of the moving body is preferably, for example, 50 mm or less, and more preferably 25 mm or less. Specifically, the width of the first region in the direction intersecting the traveling direction of the moving body is preferably 0.2 mm or more and 50 mm or less, and more preferably 1 mm or more and 25 mm or less. When the width of the first region in the direction intersecting the traveling direction of the moving body is within the above range, a large vortex V is generated near the boundary between the first region 2 and the second region 3, as shown in FIG. 10(b), for example, and the vortex V can be generated throughout the entire boundary layer.

[0070] It is more preferable that the width of the first region in the direction intersecting the traveling direction of the moving body is the same as the boundary layer thickness. Furthermore, since the boundary layer thickness decreases as the gas flow velocity increases, it is preferable that the width of the first region in the direction intersecting the traveling direction of the moving body decreases within the above range as the gas flow velocity increases.

[0071] The width of the first region in the direction intersecting the traveling direction of the moving body may be the same as or different from the width of the second region in the direction intersecting the traveling direction of the moving body, as described below, as long as it is within the above range. It is particularly preferable that the width of the first region in the direction intersecting the traveling direction of the moving body and the width of the second region in the direction intersecting the traveling direction of the moving body are the same. In this case, vortices can be generated more efficiently near the boundary between the first region and the second region.

[0072] The width W1 of the first region 2 in the direction D2 intersecting the traveling direction of the moving body refers to the distance from one end to the other end of the first region 2 in the direction D2 intersecting the traveling direction of the moving body, as shown in Figures 1(a) and 1(b), for example. Furthermore, if the surface of the gas drag reduction structure 1 is flat, as shown in Figure 1(b), for example, the width of the first region in the direction intersecting the traveling direction of the moving body refers to the width W1 of the first region 2 on the flat surface in the direction D2 intersecting the traveling direction of the moving body. Furthermore, if the surface of the gas drag reduction structure 1 is curved, as shown in Figure 11(b), for example, the width of the first region in the direction intersecting the traveling direction of the moving body refers to the width W1 of the first region 2 on the curved surface in the direction D2 intersecting the traveling direction of the moving body.

[0073] In the gas drag reduction structure of the present disclosure, it is preferable that the length L1 of the first region 2 in the traveling direction D1 of the moving body is equal to or greater than a predetermined value, thereby enabling the vortex V to be efficiently generated near the boundary between the first region 2 and the second region 3.

[0074] The length of the first region in the traveling direction of the moving body is 30 mm or more, preferably 50 mm or more. If the length of the first region in the traveling direction of the moving body is too short, vortices may not be easily generated near the boundary between the first region and the second region, and the effect of suppressing flow separation may be reduced. Furthermore, by having the length of the first region in the traveling direction of the moving body within the above range, vortices can be efficiently generated near the boundary between the first region and the second region. On the other hand, the length of the first region in the traveling direction of the moving body is not particularly limited, but is preferably 1000 mm or less, and more preferably 200 mm or less. If the length of the first region in the traveling direction of the moving body is too long, even if pressure resistance can be reduced, frictional resistance may increase, and the effect of reducing gas resistance may be reduced. Furthermore, manufacturing costs may increase. Specifically, the length of the first region in the traveling direction of the moving body is preferably 30 mm or more and 1000 mm or less, more preferably 50 mm or more and 1000 mm or less, and even more preferably 50 mm or more and 200 mm or less.

[0075] The length L1 of the first region 2 in the traveling direction D1 of the moving body refers to the distance from one end of the first region 2 to the other end of the first region 2 in the traveling direction D1 of the moving body, as shown in FIG. 1(a), for example. Specifically, as will be described later, if a convex portion in the first region protrudes from the surface of the second region, the length of the first region in the traveling direction of the moving body refers to the distance from the end of the convex portion located at one end of the first region to the end of the convex portion located at the other end of the first region in the traveling direction of the moving body. On the other hand, as will be described later, if a concave portion in the first region is recessed from the surface of the second region, the length of the first region in the traveling direction of the moving body refers to the distance from the end of the concave portion located at one end of the first region to the end of the concave portion located at the other end of the first region in the traveling direction of the moving body. Furthermore, if the surface of the gas drag reduction structure 1 is flat, as shown in FIG. 1(c), for example, the length of the first region in the traveling direction of the moving body refers to the length L1 of the first region 2 on the plane in the traveling direction D1 of the moving body, as shown in FIG. 1(a), for example. Furthermore, for example, as shown in Figure 11(a), when the surface of the gas drag reduction structure 1 is curved, the length of the first region in the traveling direction of the moving body refers to the length L1 of the first region 2 on the curved surface in the traveling direction D1 of the moving body.

[0076] Therefore, in the present disclosure, the gas resistance reduction structure has a first region having a concave-convex structure on the surface facing the resin layer and a second region adjacent to the first region. The length of the first region in the direction of travel of the moving body is equal to or greater than a predetermined value, the height of the convex portion is within a predetermined range, and the width of the first region and the width of the second region in a direction intersecting the direction of travel of the moving body are within a predetermined range. This allows vortices to be efficiently generated near the boundary between the first region and the second region. Furthermore, vortices can be generated near the boundary between the first region and the second region, and the vortices can be enlarged in the direction extending along the boundary between the first region and the second region. This effectively suppresses flow separation from the surface of the gas resistance reduction structure. Therefore, by applying the gas resistance reduction structure of the present disclosure to the surface of an object, pressure resistance, which is a component of gas resistance, can be reduced. Furthermore, with this configuration, the benefit of pressure resistance reduction can be greater than the increase in frictional resistance due to the first region.

[0077] In addition, in the first region, the convex portions may protrude relative to the surface of the second region, and the concave portions may be recessed relative to the surface of the second region. Figures 2 and 13(b) show examples in which the convex portions 11 in the first region 2 protrude relative to the surface of the second region 3, while Figures 12 and 14(b) show examples in which the concave portions 12 in the first region 2 are recessed relative to the surface of the second region 3.

[0078] In particular, it is preferable that the convex portion protrude from the surface of the second region, which makes it easier to generate vortices near the boundary between the first region and the second region.

[0079] When the convex portions protrude from the surface of the second region, the bottoms of the concave portions 5 are usually located on the same plane as the surface of the second region 3, as shown in Fig. 2 for example. When the concave portions are recessed from the surface of the second region, the tops of the convex portions 11 are usually located on the same plane as the surface of the second region 3, as shown in Fig. 12 for example.

[0080] The first region has a concave-convex structure including convex portions and concave portions, and it is sufficient that the convex portions and concave portions are uniformly distributed in the first region.

[0081] The pattern shape of the convex portions and concave portions in plan view may be, for example, a regular pattern or a random pattern. In the case of a regular pattern, examples include a line pattern, a dot pattern, a lattice pattern, and the like.

[0082] Examples of the line pattern include straight lines and wavy line patterns such as sine waves and triangular waves. Of these, the line pattern is preferably a straight line pattern.

[0083] In the dot pattern, the dots may be arranged in a parallel arrangement or a staggered arrangement, for example.

[0084] Examples of the lattice pattern include a square lattice pattern, a rectangular lattice pattern, a triangular lattice pattern, a hexagonal lattice pattern, a rhombic lattice pattern, and a parallelogram lattice pattern.

[0085] FIG. 2 shows an example in which the pattern shape of the convex portions 11 in a plan view is linear. FIG. 12 shows an example in which the pattern shape of the concave portions 12 in a plan view is linear. FIGS. 13(a) to 13(c) show examples in which the pattern shape of the convex portions 11 in a plan view is a dotted pattern in a staggered arrangement. FIGS. 13(b) and 13(c) are cross-sectional views taken along line AA in FIG. 13(a). FIGS. 14(a) to 14(b) show examples in which the pattern shape of the concave portions 12 in a plan view is a dotted pattern in a staggered arrangement. FIG. 14(b) is a cross-sectional view taken along line AA in FIG. 14(a). FIG. 15 shows an example in which the pattern shape of the convex portions 11 in a plan view is a lattice pattern, a rectangular lattice pattern.

[0086] When the pattern shape of the convex portions and recessed portions in a plan view is linear, the longitudinal direction of the linear pattern of the convex portions and recessed portions preferably intersects with the traveling direction of the moving body, and more preferably is substantially perpendicular to the traveling direction of the moving body, i.e., is substantially parallel to the direction intersecting with the traveling direction of the moving body. Specifically, when the pattern shape of the convex portions and recessed portions is linear, the longitudinal direction of the linear pattern of the convex portions and recessed portions preferably intersects with the traveling direction of the moving body, and is preferably substantially perpendicular to the traveling direction of the moving body, i.e., is substantially parallel to the direction intersecting with the traveling direction of the moving body, as shown in FIG. 3 for example. That is, the first region preferably has convex portions and recessed portions that extend linearly along the direction intersecting with the traveling direction of the moving body. As will be described later, in the moving body, the gas resistance reducing structure is, for example, as shown in FIG. 3(a), parallel to the traveling direction D1 of the moving body, i.e., the flow direction d of the gas F. F It is preferable that the boundary between the first region 2 and the second region 3 is arranged so as to be approximately parallel to the moving body. Therefore, when the longitudinal direction of the linear pattern of the protrusions and recesses intersects with the moving body's direction of travel, the longitudinal direction of the linear pattern of the protrusions and recesses can be made to intersect with the gas flow direction. In such a case, vortices can be more easily generated near the boundary between the first region and the second region. Furthermore, when the longitudinal direction of the linear pattern of the protrusions and recesses is approximately perpendicular to the moving body's direction of travel, the longitudinal direction of the linear pattern of the protrusions and recesses can be made to be approximately perpendicular to the gas flow direction. In such a case, vortices can be even more easily generated near the boundary between the first region and the second region.

[0087] Furthermore, when the longitudinal direction of the linear pattern of the convex portions and concave portions intersects with the traveling direction of the moving body, the angle formed by the longitudinal direction of the linear pattern and the traveling direction of the moving body is preferably, for example, 45° to 135°. Similarly, when the longitudinal direction of the linear pattern of the convex portions and concave portions intersects with the traveling direction of the moving body, the angle formed by the longitudinal direction of the linear pattern and the traveling direction of the moving body is preferably, for example, 45° to 135°.

[0088] "The longitudinal direction of the linear pattern of convex portions and concave portions being substantially perpendicular to the traveling direction of the moving body" means that the angle between the longitudinal direction of the linear pattern and the traveling direction of the moving body is 85° or more and 95° or less. Similarly, "The longitudinal direction of the linear pattern of convex portions and concave portions being substantially perpendicular to the traveling direction of the moving body" means that the angle between the longitudinal direction of the linear pattern and the traveling direction of the moving body is 85° or more and 95° or less.

[0089] The longitudinal direction of a line pattern refers to the direction in which the linear pattern extends in the case of a straight line pattern, and refers to the direction in which the wavy line pattern extends in the case of a wavy line pattern, for example.

[0090] Therefore, the angle between the longitudinal direction of the line-shaped pattern and the traveling direction of the moving body is, for example, preferably 45° to 135°, more preferably 80° to 100°, and even more preferably 85° to 95°. Furthermore, when the line shape is linear, the angle between the longitudinal direction of the linear pattern and the traveling direction of the moving body is, for example, preferably 45° to 135°, more preferably 80° to 100°, and even more preferably 85° to 95°.

[0091] When the pattern shape of the convex portions and concave portions in a planar view is linear, the width of the linear convex portions is preferably, for example, 1 to 2 times the height of the convex portions. Specifically, when the pattern shape of the convex portions is linear, the width of the linear convex portions is preferably 1 to 2 times the height of the convex portions. If the width of the linear convex portions is too small, it may be difficult to form the first region. Furthermore, if the width of the linear convex portions is too large, it may be difficult to sufficiently generate vortices near the boundary between the first region and the second region.

[0092] The width of the linear convex portion is, for example, width W3 of the convex portion 11 as shown in FIGS. 16(a) to 16(i), and refers to the largest width of the convex portion 11.

[0093] Furthermore, when the pattern shape of the convex portions in plan view is linear, the width of the linear recesses is, for example, preferably 1 time or more, and more preferably 4 times or more, the height of the convex portions. On the other hand, the width of the linear recesses is, for example, preferably 12 times or less, and more preferably 10 times or less, the height of the convex portions. On the other hand, the width of the linear recesses is, for example, preferably 1 time or more and 12 times or less, and more preferably 4 times or more and 10 times or less, the height of the convex portions. Specifically, when the pattern shape of the convex portions in plan view is linear, the width of the linear recesses is, for example, preferably 1 time or more and more preferably 4 times or more, the height of the convex portions. On the other hand, the width of the linear recesses is, for example, preferably 12 times or less, and more preferably 10 times or less, the height of the convex portions. On the other hand, the width of the linear recesses is, for example, preferably 12 times or less, and more preferably 10 times or less, the height of the convex portions. On the other hand, the width of the linear recesses is, for example, preferably 1 time or more and 12 times or less, and more preferably 4 times or more and ... If the width of the linear depressions is too small, the density of the protrusions will be high, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions. If the width of the linear depressions is too large, the density of the protrusions will be low, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions. If the width of the linear depressions is between 4 and 10 times the height of the protrusions, vortices can be generated near the boundary between the first and second regions, effectively suppressing flow separation.

[0094] The width of the linear recess is, for example, width W4 of recess 12 as shown in Figures 16(a) to 16(i), and refers to the smallest width of recess 12. For example, in Figure 16(d) and Figures 16(g) to 16(i), the width of recess 12 is zero.

[0095] Furthermore, when the pattern shape of the convex portions and concave portions in plan view is linear, the pitch of the linear convex portions is, for example, preferably at least twice the height of the convex portions, and more preferably at least five times. On the other hand, the pitch of the linear convex portions is, for example, preferably at most 14 times the height of the convex portions, and more preferably at most 12 times. Also, the pitch of the linear convex portions is, for example, preferably at least 2 times but not more than 14 times the height of the convex portions, and more preferably at least 5 times but not more than 12 times. Specifically, when the pattern shape of the convex portions in plan view is linear, the pitch of the linear convex portions is, for example, preferably at least 2 times but not more than 5 times the height of the convex portions. On the other hand, the pitch of the linear convex portions is, for example, preferably at most 14 times but not more than 12 times the height of the convex portions, and more preferably at least 5 times but not more than 12 times. Also, the pitch of the linear convex portions is, for example, preferably at least 2 times but not more than 14 times the height of the convex portions, and more preferably at least 5 times but not more than 12 times. If the pitch of the linear protrusions is too small, the density of the protrusions will be high, which may make it difficult to generate a sufficient vortex near the boundary between the first and second regions, whereas if the pitch of the linear protrusions is too large, the density of the protrusions will be low, which may make it difficult to generate a sufficient vortex near the boundary between the first and second regions.

[0096] The pitch of the linear convex portions is, for example, the pitch P1 of the convex portions 11 as shown in FIGS. 16(a) to 16(i), and refers to the distance between adjacent convex portions 11.

[0097] Furthermore, when the pattern shape of the convex portions in a planar view is dot-shaped, the size of the dot-shaped convex portions in a planar view is preferably, for example, one to two times the height of the convex portions. If the size of the dot-shaped convex portions is too small, it may be difficult to form the first region. If the size of the dot-shaped convex portions is too large, it may be difficult to sufficiently generate vortices near the boundary between the first region and the second region.

[0098] Furthermore, when the pattern shape of the recesses in a planar view is dot-shaped, the size of the dot-shaped recesses in a planar view is, for example, preferably at least 1 time, more preferably at least 4 times, the height of the protrusions. On the other hand, the size of the dot-shaped recesses in a planar view is, for example, preferably at most 12 times, more preferably at most 10 times the height of the protrusions. Furthermore, the size of the dot-shaped recesses in a planar view is, for example, preferably at least 1 time and at most 12 times, more preferably at most 4 times and at most 10 times the height of the protrusions. If the size of the dot-shaped recesses is too small, the density of the protrusions will be high, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions. If the size of the dot-shaped recesses is too large, the density of the protrusions will be low, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions. If the size of the dot-shaped recesses is at least 4 times and at most 10 times the height of the protrusions, vortices will be generated near the boundary between the first and second regions, which may effectively suppress flow separation.

[0099] The size of the dot-shaped convex portions in a plan view refers to, for example, the diameter when the convex portions are circular in plan view, the major axis when the convex portions are elliptical in plan view, and the length of the diagonal when the convex portions are rectangular in plan view. Similarly, the size of the dot-shaped concave portions in a plan view refers to, for example, the diameter when the concave portions are circular in plan view, the major axis when the concave portions are elliptical in plan view, and the length of the diagonal when the concave portions are rectangular in plan view.

[0100] Furthermore, when the pattern shape of the convex portions or concave portions in a planar view is dot-shaped, the pitch of the dot-shaped convex portions or concave portions is, for example, preferably at least twice the height of the convex portions, and more preferably at least five times. On the other hand, the pitch of the dot-shaped convex portions or concave portions is, for example, preferably at most 14 times the height of the convex portions, and more preferably at most 12 times. Furthermore, the pitch of the dot-shaped convex portions or concave portions is, for example, preferably at least 2 times but not more than 14 times the height of the convex portions, and more preferably at least 5 times but not more than 12 times. If the pitch of the dot-shaped convex portions or concave portions is too small, the density of the convex portions will be high, which may make it difficult to sufficiently generate vortices near the boundary between the first and second regions. If the pitch of the dot-shaped convex portions or concave portions is too large, the density of the convex portions will be low, which may make it difficult to sufficiently generate vortices near the boundary between the first and second regions.

[0101] The pitch of the dot-shaped convex portions refers to the distance between adjacent convex portions, and the pitch of the dot-shaped concave portions refers to the distance between adjacent concave portions.

[0102] Furthermore, when the planar pattern of the convex portions is a grid, the width of the grid-shaped convex portions is preferably, for example, one to two times the height of the convex portions. If the width of the grid-shaped convex portions is too small, it may be difficult to form the first region. If the width of the grid-shaped convex portions is too large, it may be difficult to sufficiently generate vortices near the boundary between the first region and the second region.

[0103] Furthermore, when the pattern shape of the convex portions in a planar view is a grid, the spacing between the grid-shaped convex portions is, for example, preferably at least 1 time, and more preferably at least 4 times, the height of the convex portions. On the other hand, the spacing between the grid-shaped convex portions is, for example, preferably at most 12 times, and more preferably at most 10 times, the height of the convex portions. Furthermore, the spacing between the grid-shaped convex portions is, for example, preferably at least 1 time and at most 12 times, and more preferably at least 4 times and at most 10 times, the height of the convex portions. If the spacing between the grid-shaped convex portions is too small, the density of the convex portions will be high, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions. If the spacing between the grid-shaped convex portions is too large, the density of the convex portions will be low, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions. Furthermore, if the spacing between the grid-shaped convex portions is at least 4 times and at most 10 times the height of the convex portions, vortices will be generated near the boundary between the first and second regions, and flow separation can be effectively suppressed.

[0104] Furthermore, when the pattern shape of the recesses in a planar view is a grid, the width of the grid-shaped recesses is, for example, preferably at least 1 time, and more preferably at least 4 times, the height of the protrusions. On the other hand, the width of the grid-shaped recesses is, for example, preferably at most 12 times, and more preferably at most 10 times the height of the protrusions. Furthermore, the width of the grid-shaped recesses is, for example, preferably at least 1 time and at most 12 times, and more preferably at most 4 times and at most 10 times the height of the protrusions. If the width of the grid-shaped recesses is too small, the density of the protrusions will be high, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions. If the width of the grid-shaped recesses is too large, the density of the protrusions will be low, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions. Furthermore, if the width of the grid-shaped recesses is at least 4 times and at most 10 times the height of the protrusions, vortices will be generated near the boundary between the first and second regions, which may effectively suppress flow separation.

[0105] Furthermore, when the planar pattern of the convex portions or concave portions is a lattice pattern, the pitch of the lattice-shaped convex portions or concave portions is, for example, preferably at least twice the height of the convex portions, and more preferably at least five times. On the other hand, the pitch of the lattice-shaped convex portions or concave portions is, for example, preferably at most 14 times the height of the convex portions, and more preferably at most 12 times. Furthermore, the pitch of the lattice-shaped convex portions or concave portions is, for example, preferably at least 2 times but not more than 14 times the height of the convex portions, and more preferably at least 5 times but not more than 12 times. If the pitch of the lattice-shaped convex portions or concave portions is too small, the density of the convex portions will be high, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions. If the pitch of the lattice-shaped convex portions or concave portions is too large, the density of the convex portions will be low, which may make it difficult to generate sufficient vortices near the boundary between the first and second regions.

[0106] The dimensions of the first region, the convex portion, and the concave portion are measured by a laser displacement sensor.

[0107] Furthermore, the cross-sectional shapes of the convex portions and concave portions are not particularly limited, and examples thereof include rectangular, trapezoidal, triangular, semicircular, and semi-elliptical shapes. Fig. 16(a) shows an example in which the cross-sectional shapes of the convex portions 11 and concave portions 12 are rectangular. Fig. 16(b) shows an example in which the cross-sectional shapes of the convex portions 11 and concave portions 12 are trapezoidal. Figs. 16(c) to 16(e) show an example in which the cross-sectional shape of the convex portions 11 is triangular. Fig. 16(f) shows an example in which the cross-sectional shape of the convex portions 11 is semi-elliptical. Figs. 16(g) to 16(h) show an example in which the cross-sectional shape of the concave portions 12 is triangular. Fig. 16(i) shows an example in which the cross-sectional shape of the concave portions 12 is semicircular.

[0108] Among these, the cross-sectional shape of the convex or concave portions is preferably trapezoidal, semicircular, or semi-elliptical, as these shapes make it easy to form the first region and can increase the durability of the first region.

[0109] Furthermore, it is preferable that the protrusion has a rounded shape, that is, a curved surface, in the portion extending from the top to the side of the protrusion and connected to the top.

[0110] Figures 17(a) and 17(b) are schematic cross-sectional views illustrating protrusions in the gas drag reduction structure, where Figure 17(a) is a schematic cross-sectional view of the protrusions in a direction intersecting the traveling direction of the moving body, and Figure 17(b) is a schematic cross-sectional view of the protrusions in the traveling direction of the moving body.

[0111] As illustrated in FIGS. 17(a) and 17(b), the protrusions 11 have a rounded portion 11R, which is a portion extending from the top 11T to the side 11S of the protrusions 11 and is connected to the top 11T. That is, the protrusions 11 have a curved surface at the portion 11R. When the protrusions 11 have a rounded portion 11R, the abrasion resistance and wear resistance of the protrusions 11 can be improved. Furthermore, the frictional resistance at the portion 11R on the boundary side of the protrusions 11 against vortices generated at the boundary between the first and second regions can be suppressed. Therefore, it is expected that the effect of the vortex, i.e., the effect of suppressing gas from separating from the surface, will be further enhanced.

[0112] In the above-mentioned portion of the convex portion, the radius of curvature of the curved surface is, for example, preferably 10 μm or more, more preferably 20 μm or more. On the other hand, the radius of curvature of the curved surface is, for example, preferably 400 μm or less, more preferably 200 μm or less. Specifically, the radius of curvature of the curved surface is preferably 10 μm or more and 400 μm or less, more preferably 20 μm or more and 200 μm or less. If the radius of curvature of the curved surface is excessively small, it may be difficult to improve the scratch resistance and abrasion resistance of the gas drag reduction structure. Furthermore, if the radius of curvature of the curved surface is excessively large, the height of the convex portion must also be increased. If the height of the convex portion exceeds a size suitable for reducing gas drag, the gas drag reduction effect may be insufficient.

[0113] The radius of curvature of the curved surface at the above-mentioned portion of the convex portion refers to the radius of curvature of the curve at the above-mentioned portion of the convex portion in a cross section in the thickness direction of the gas drag reduction structure. For example, Fig. 17(a) is a cross section in the thickness direction of the gas drag reduction structure, which is a cross section of the convex portion in a direction intersecting the traveling direction of the moving body. Also, for example, Fig. 17(b) is a cross section in the thickness direction of the gas drag reduction structure, which is a cross section of the convex portion in the traveling direction of the moving body. In Figs. 17(a) and 17(b), the radius of curvature of the curved surface at the above-mentioned portion 11R of the convex portion 11 is the radius of curvature r1 of the curve at the above-mentioned portion 11R of the convex portion 11.

[0114] Furthermore, the first region has a plurality of convex or concave portions, which are appropriately set to satisfy the above-described dimensions of the first region, the convex portions, and the concave portions. Specifically, the number of convex or concave portions in the first region is 14 or more, or may be 83 or more, or 181 or more. On the other hand, the number of convex or concave portions may be, for example, 1500 or less, or may be 714 or less, or may be 200 or less. Specifically, the number of convex or concave portions may be 14 or more and 1500 or less, or may be 83 or more and 714 or less, or may be 181 or more and 200 or less. By keeping the number of convex or concave portions within the above range, it is possible to maximize the reduction in pressure resistance and minimize the increase in frictional resistance. This makes it possible to maximize the gas resistance reduction effect.

[0115] The planar shape of the first region is not particularly limited as long as it can generate a vortex near the boundary between the first region and the second region, and examples thereof include a rectangular shape and an arc shape. For example, Fig. 1 shows an example in which the planar shape of the first region 2 is rectangular, and Fig. 18 shows an example in which the planar shape of the first region 2 is rectangular and an arc shape. Among these, a rectangular shape is preferable as the planar shape of the first region.

[0116] (2)Second area In the gas drag reduction structure of the present disclosure, the second region is adjacent to the first region.

[0117] The width of the second region in the direction intersecting the traveling direction of the moving body is 0.2 mm or more, and preferably 1 mm or more. On the other hand, the width of the second region in the direction intersecting the traveling direction of the moving body is 50 mm or less, and preferably 25 mm or less. Specifically, the width of the second region in the direction intersecting the traveling direction of the moving body is 0.2 mm or more and 50 mm or less, and preferably 1 mm or more and 25 mm or less. By having the width of the second region in the direction intersecting the traveling direction of the moving body within the above range, a large vortex V is generated near the boundary between the first region 2 and the second region 3, as shown in FIG. 10(b), for example, and the vortex V can be generated throughout the entire boundary layer.

[0118] The width of the second region in the direction intersecting the traveling direction of the moving body is preferably the same as the boundary layer thickness. Furthermore, since the boundary layer thickness decreases as the gas flow velocity increases, the width of the second region in the direction intersecting the traveling direction of the moving body is preferably smaller within the above range as the gas flow velocity increases.

[0119] The width W2 of the second region 3 in the direction D2 intersecting the traveling direction of the moving body refers to the distance from one end of the second region 3 to the other end of the second region 3 in the direction D2 intersecting the traveling direction of the moving body, for example, as shown in Figures 1(a) and 1(b) when the second region 3 is located between adjacent first regions 2. Furthermore, for example, as shown in Figure 1(b), if the surface of the gas drag reduction structure 1 is flat, the width of the second region in the direction intersecting the traveling direction of the moving body refers to the width W2 of the second region 3 on the flat surface in the direction D2 intersecting the traveling direction of the moving body. Furthermore, for example, as shown in Figure 11(b), if the surface of the gas drag reduction structure 1 is curved, the width of the second region in the direction intersecting the traveling direction of the moving body refers to the width W2 of the second region 3 on the curved surface in the direction D2 intersecting the traveling direction of the moving body.

[0120] (3) Area 1 and Area 2 The gas drag reduction structure according to the present disclosure has a first region and a second region adjacent to the first region, and the first region and the second region extend in a band shape in the traveling direction of the moving body.

[0121] In the present disclosure, since vortices are generated near the boundary between the first region and the second region, it is sufficient to arrange at least one first region and at least one second region. In particular, it is preferable that the first region and the second region are arranged alternately in a direction intersecting the traveling direction of the moving body.

[0122] When the first and second regions are alternately arranged in a direction intersecting the traveling direction of the mobile body, for example, the first and second regions may be alternately arranged parallel to the traveling direction of the mobile body, or alternately arranged non-parallel to the traveling direction of the mobile body. For example, FIG. 1(a) shows an example in which the first regions 2 and the second regions 3 are alternately arranged parallel to the traveling direction D2 intersecting the traveling direction of the mobile body, and FIG. 18 shows an example in which the first regions 2 and the second regions 3 are alternately arranged non-parallel to the traveling direction D2 intersecting the traveling direction of the mobile body. For example, when the gas drag reduction structure is applied to a three-dimensional curved surface of the mobile body, the first and second regions may be alternately arranged non-parallel to the traveling direction of the mobile body. In particular, it is preferable that the first and second regions be alternately arranged parallel to the traveling direction of the mobile body.

[0123] (4) The direction of travel of the moving object and the direction intersecting the direction of travel of the moving object The direction intersecting the traveling direction of the moving body may be any direction as long as it intersects with the traveling direction of the moving body, but it is preferable that it be perpendicular to the traveling direction of the moving body. The angle between the traveling direction of the moving body and the direction intersecting with the traveling direction of the moving body is, for example, preferably 85° to 95°, and more preferably 90°.

[0124] The gas resistance reduction structure is preferably arranged so that the angle formed by the boundary line between the first region and the second region and the traveling direction of the moving body is, for example, not less than −15° and not more than 15°.

[0125] In particular, it is more preferable that the gas drag reduction structure be arranged so that the boundary between the first region 2 and the second region 3 is approximately parallel to the traveling direction D1 of the moving body, as shown in Figure 1(a), for example. This makes it easier to generate vortices near the boundary between the first region and the second region, and suppresses flow separation.

[0126] The boundary between the first and second regions being approximately parallel to the traveling direction of the moving body means that the angle between the boundary between the first and second regions and the traveling direction of the moving body is between -5° and 5°.

[0127] Therefore, it is preferable that the gas resistance reduction structure be positioned and used so that the angle between the boundary line between the first and second regions and the direction of travel of the moving body is, for example, between -15° and 15°, particularly between -10° and 10°, and particularly between -5° and 5°.

[0128] (3) Configuration of the gas drag reduction structure In the present disclosure, the gas drag reduction structure may be configured as a separate body from the moving body, or may be configured as an integral part of the moving body.

[0129] Below, the case where the gas resistance reduction structure is separate from the moving body and the case where the gas resistance reduction structure is integrated with the moving body will be described separately.

[0130] (a) When the gas drag reduction structure is separate from the moving body When the gas resistance reduction structure is configured as a separate body from the moving body, for example, a member having the gas resistance reduction structure on its surface can be used and disposed on the surface of the moving body.

[0131] Examples of members having a gas resistance reducing structure on their surface include resin members having a gas resistance reducing structure on their surface, metal members having a gas resistance reducing structure on their surface, and ceramic members having a gas resistance reducing structure on their surface.

[0132] As will be described later, when the resin member is a resin film and when the metal member is a metal sheet, these members are usually attached to the surface of the moving body. In this case, the moving body becomes a moving body to which the gas resistance reduction structure is attached.

[0133] Furthermore, as will be described later, when the resin member is a resin molded product, when the metal member is a metal part, and when the ceramic member is a ceramic molded product, these members are usually attached to the surface of the moving body or mechanically joined by caulking, screws, etc. In this case, the moving body becomes a moving body equipped with a gas drag reduction structure.

[0134] (i) Resin materials Examples of resin members having a gas resistance reducing structure on their surface include resin films having a gas resistance reducing structure on their surface, and resin molded articles having a gas resistance reducing structure on their surface.

[0135] (i-1) Resin film The resin film has a gas resistance reducing structure on the surface.

[0136] (i-1-1) Textured resin film The resin film may have at least a concave-convex resin film having a gas resistance reducing structure on the surface thereof.

[0137] The uneven resin film may have at least a resin substrate. The uneven resin film may have a gas resistance-reducing structure on its surface. For example, in an uneven resin film 31, the uneven structure of the first region 2 may be integral with the resin substrate 32 as shown in FIGS. 19(a) and 19(b). Alternatively, the uneven structure of the first region 2 may be formed separately from the resin substrate 32 as shown in FIGS. 19(c) to 19(f). When the uneven structure of the first region is formed separately from the resin substrate, the bottoms of the recesses 12 of the uneven structure of the first region 2 and the second region 3 may be on the surface of the resin substrate 32 as shown in FIGS. 19(c) and 19(d). Alternatively, a resin layer 33 may be disposed on one surface of the resin substrate 32, and the resin layer 33 may have the first region 2 and the second region 3 as shown in FIGS. 19(e) to 19(f).

[0138] The first region may be transparent or opaque.

[0139] The material for the concave-convex structure of the first region can be a resin. When the concave-convex structure of the first region is integrally formed with the resin substrate, the material for the concave-convex structure of the first region is the same as the material for the resin substrate described below. When the concave-convex structure of the first region is formed separately from the resin substrate, examples of the material for the concave-convex structure of the first region include a cured product of an ionizing radiation-curable resin composition such as an ultraviolet-curable resin composition or an electron beam-curable resin composition, or a curable resin composition such as a thermosetting resin composition, and a thermoplastic resin.

[0140] Furthermore, the concave-convex structure of the first region may contain additives such as ultraviolet absorbers, antioxidants, plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, antistatic agents, and flame retardants, as needed. When the concave-convex structure of the first region contains an ultraviolet absorber, weather resistance can be improved.

[0141] The method for forming the uneven structure of the first region may be, for example, a method for forming an uneven structure on a resin substrate, or a method for forming an uneven shape on one surface of a resin substrate.

[0142] Examples of methods for forming a relief structure on a resin substrate include a method in which a curable resin composition is applied to a resin substrate in a predetermined pattern and then cured; a photopolymer method (2P method) in which an ultraviolet-curable resin composition is applied to a resin substrate, a mold is pressed against the coating, ultraviolet light is irradiated to cure the ultraviolet-curable resin composition, and then the resin is peeled off from the mold; a lithography method in which an ionizing radiation-curable resin composition is applied to a resin substrate, and the resin substrate is irradiated with ionizing radiation such as ultraviolet light or an electron beam in a pattern and developed; and a method in which a resin layer is formed on a resin substrate and the surface of the resin layer is embossed. Alternatively, a resin layer with an embossed surface may be separately prepared and then laminated on the resin substrate.

[0143] In the case of a method in which a curable resin composition is applied to a resin substrate in a predetermined pattern and then cured, the method for applying the curable resin composition is not particularly limited as long as it can be applied in a desired pattern, and examples thereof include an inkjet method, a screen printing method, etc. In addition, in the case of the 2P method or the lithography method, the method for applying the curable resin composition is not particularly limited as long as it can be applied uniformly, and any known application method can be used.

[0144] In the case of the embossing method, the material of the resin layer is not particularly limited as long as it is embossable, and a thermoplastic resin can be used. In this case, the thickness of the resin layer is not particularly limited as long as it is greater than the height of the convex portions of the concave-convex structure of the first region, and is approximately 30 μm to 300 μm.

[0145] Examples of methods for forming an uneven shape on one surface of a resin substrate include embossing such as single-side embossing or double-side embossing, and laser processing.

[0146] When the resin substrate is integrally formed with the concave-convex structure of the first region, the material of the resin substrate can be, for example, a thermoplastic resin, and can be appropriately selected from general-purpose plastics and engineering plastics. Among them, vinyl chloride resin is preferred from the viewpoints of weather resistance and abrasion resistance.

[0147] Furthermore, the resin substrate may contain additives such as plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, UV absorbers, antioxidants, antistatic agents, and flame retardants, as needed. When the resin substrate is integrally formed with the uneven structure of the first region and contains an UV absorber, weather resistance can be improved.

[0148] The resin substrate may be transparent or opaque.

[0149] The thickness of the resin substrate is not particularly limited, but is about 80 μm or more and 350 μm or less.

[0150] (i-1-2) Other configurations of resin film The resin film may further have other components in addition to the uneven resin film.

[0151] (Adhesive layer) 20(a), the resin film 30 may have an adhesive layer 34 on the surface of the first region 2 of the uneven resin film 31 opposite to the uneven structure. The adhesive layer is a layer for attaching the resin film to the surface of a moving object. By having the adhesive layer on the resin film, the resin film can be easily attached to the surface of a moving object.

[0152] The adhesive used in the adhesive layer is appropriately selected depending on the use of the resin film, and examples thereof include acrylic adhesives, urethane adhesives, silicone adhesives, rubber adhesives, and vinyl ether adhesives.

[0153] The adhesive layer may or may not have removability, but is preferably removably. When the adhesive layer has removability, the resin film can be reattached to the surface of the movable body, and when the resin film is reattached or removed, the resin film can be peeled from the movable body without leaving any adhesive residue.

[0154] The term "removable" refers to the property that after a resin film is attached to the surface of a mobile object, it can be easily removed without destroying the mobile object and without leaving any adhesive on the surface of the mobile object.

[0155] The adhesive layer may also contain a colorant. By containing a colorant in the adhesive layer, it is possible to impart shielding properties. For example, when a design is applied to the surface of a mobile object, if the adhesive layer contains a colorant and the resin film further has a printed layer as described below, the design can be hidden and a new design can be applied by attaching the resin film to the surface of the mobile object.

[0156] The thickness of the adhesive layer is not particularly limited and is appropriately selected depending on the application, etc. For example, when the resin film is used as a wrapping film or marking film for a moving body such as an automobile, a train, or an airplane, the thickness of the adhesive layer is about 5 μm or more and 50 μm or less. If the thickness of the adhesive layer is too thin, there is a possibility that the adhesion to the moving body will be insufficient.

[0157] Examples of methods for forming the adhesive layer include a method of applying an adhesive composition and a method of laminating an adhesive film.

[0158] (Printing layer) The resin film may have a printed layer on the surface opposite to the first region of the uneven resin film. By having a printed layer on the resin film, it is possible to impart design properties.

[0159] The print layer can display information such as letters, numbers, symbols, pictures, patterns, and marks.

[0160] The printing layer may be formed, for example, by printing directly on the resin substrate of the uneven resin film, or by printing on a support layer 35 to form a printing layer 36, as shown in FIG. 20(b). The printing layer may be arranged in a pattern on the resin substrate or support layer, or may be arranged over the entire surface of the resin substrate or support layer. The printing method is not particularly limited.

[0161] The support layer is not particularly limited as long as it can be printed, and for example, a resin substrate can be used.

[0162] The support layer may also contain a colorant. By including a colorant in the support layer, it is possible to impart shielding properties. For example, when a design is applied to the surface of a mobile object, if the resin film has a printed layer and the support layer contains a colorant, the design can be hidden and a new design can be applied by attaching a resin film to the surface of the mobile object.

[0163] The thickness of the support layer is not particularly limited and may be appropriately selected depending on the application.

[0164] Furthermore, when forming a printed layer by printing on a support layer, for example, as shown in Figure 30(b), a printed sheet having a support layer 35 and a printed layer 36 arranged on one side of the support layer 63 may be separately prepared, and this printed sheet may be attached to the uneven resin film 31 via a second adhesive layer 37, or the printed layer, resin substrate, and resin layer may be formed in that order on the support layer.

[0165] (protective layer) The resin film may have a protective layer on the surface of the first region of the uneven resin film facing the uneven structure, which can protect the first region and improve abrasion resistance.

[0166] When a protective layer is disposed on the surface of the first region of the uneven resin film facing the uneven structure, it is preferable that the dimensions of the unevenness on the surface of the resin film facing the protective layer satisfy the dimensions of the uneven structure of the first region described above.

[0167] The protective layer may be made of, for example, a resin, of which electron beam curable resin and fluororesin are preferred from the viewpoints of weather resistance and abrasion resistance.

[0168] Furthermore, the protective layer may contain additives such as ultraviolet absorbers, antioxidants, plasticizers, stabilizers, lubricants, fillers, colorants, processing aids, antistatic agents, and flame retardants, as required. When the protective layer contains an ultraviolet absorber, weather resistance can be improved.

[0169] The thickness of the protective layer is preferably, for example, 0.01 μm or more and 10 μm or less.

[0170] (i-1-3) Resin film placement method As a method for disposing a resin film on the surface of a moving body, for example, a method of adhering it using a pressure sensitive adhesive or adhesive agent can be mentioned.

[0171] (i-2) Resin molded products The resin molded article has a gas resistance reducing structure on the surface.

[0172] The material for the resin molded product may be a thermoplastic resin, which may be appropriately selected from general-purpose plastics and engineering plastics, among which acrylic resins and polycarbonates are preferred from the viewpoints of weather resistance and abrasion resistance.

[0173] The method for producing a resin molded article is not particularly limited as long as it is a method that can produce a resin molded article having a gas drag reducing structure on the surface, and examples thereof include injection molding and extrusion molding.

[0174] Methods for placing a resin molded product on the surface of a moving body include, for example, adhesion using a pressure sensitive adhesive or adhesive, caulking, screw fastening, and the like.

[0175] (ii) Metallic components Examples of metal members having a gas resistance reducing structure on their surface include metal sheets having a gas resistance reducing structure on their surface, and metal parts having a gas resistance reducing structure on their surface.

[0176] (ii-1) Metal sheet The metal sheet may have at least a metal layer having a gas drag reduction structure on its surface.

[0177] The material for the metal layer is not particularly limited as long as it is a material that can produce a metal layer having a gas drag reduction structure on its surface, and examples include aluminum, aluminum alloys, titanium, titanium alloys, copper, iron, and stainless steel.

[0178] Examples of methods for forming the first region on the surface of the metal layer include press processing (embossing), rolling, end mill processing, laser processing, and lithography.

[0179] The thickness of the metal layer is not particularly limited and may be appropriately selected depending on the intended use.

[0180] (ii-1-2) Other configurations of metal sheets The metal sheet may further include other components in addition to the metal layer.

[0181] (Adhesive layer) The metal sheet may have an adhesive layer on the surface of the metal layer opposite to the first region. The adhesive layer is a layer for attaching the metal sheet to the surface of a movable body. By having the adhesive layer on the metal sheet, the metal sheet can be easily attached to the surface of a movable body.

[0182] The adhesive layer is the same as the adhesive layer used in the resin film.

[0183] (ii-1-3) Metal sheet placement method As a method for placing a metal sheet on the surface of a moving body, for example, a method of adhering it using a pressure sensitive adhesive or adhesive can be mentioned.

[0184] (ii-2) Metal parts The metal part has a gas drag reduction structure on the surface.

[0185] The material for the metal parts is not particularly limited as long as it is a material that can be used to obtain metal parts having a gas resistance reducing structure on the surface, and examples include aluminum, aluminum alloys, titanium, titanium alloys, copper, iron, stainless steel, etc.

[0186] Methods for forming the first region on the surface of a metal part include, for example, press processing (embossing), end mill processing, laser processing, and modeling using a metal 3D printer.

[0187] Methods for placing metal parts on the surface of a moving body include, for example, welding, bonding using a pressure sensitive adhesive or adhesive, crimping, screw fastening, and the like.

[0188] (iii) Ceramic components Examples of ceramic members having a gas resistance reducing structure on the surface include ceramic molded articles having a gas resistance reducing structure on the surface.

[0189] As the material for the ceramic molded product, for example, fine ceramics can be used.

[0190] The method for producing a ceramic molded article is not particularly limited as long as it is a method capable of producing a ceramic molded article having a gas drag reducing structure on the surface thereof, and examples thereof include injection molding and extrusion molding.

[0191] Methods for placing the ceramic molded product on the surface of the moving body include, for example, adhesion using a pressure sensitive adhesive or adhesive, caulking, screw fastening, and the like.

[0192] (b) When the gas drag reduction structure is integrated with the moving body When the gas resistance reduction structure is configured as an integral part of a moving body, the gas resistance reduction structure is formed directly on the surface of the moving body. When the gas resistance reduction structure is formed directly on the surface of a moving body, for example, the gas resistance reduction structure can be formed directly on the surface of a vehicle body or part of an automobile, railway vehicle, or the like, or the body or part of an aircraft.

[0193] The material that constitutes the gas drag reduction structure is appropriately selected depending on the vehicle body or its parts, or the aircraft or its parts, on which the gas drag reduction structure is formed, and examples thereof include metallic materials such as metals and alloys, resin materials such as resins and fiber-reinforced resins, and ceramic materials such as glass and fine ceramics.

[0194] The method for forming the gas drag reduction structure directly on the surface of the moving body is appropriately selected depending on the material and the like.

[0195] For example, in the case of metal materials, examples of methods include end mill processing, laser processing, and shaping using a metal 3D printer. In addition, in the case of metal materials, first, the above-mentioned uneven resin film is used as an original plate, and a water-soluble resin composition is applied to the surface of the uneven structure side of the uneven resin film (original plate), dried and solidified, and then peeled off from the uneven resin film (original plate) to prepare a stamper made of the water-soluble resin film. Next, a surface coating agent is applied to the surface of the moving body, and the water-soluble resin film (stamper) is pressed against the coating film. The surface coating agent is cured, and then the water-soluble resin film (stamper) is dissolved and removed with water. In this method, for example, a common paint used for painting automobiles, railway vehicles, aircraft, etc. can be used as the surface coating agent. In addition, in the case of metal materials, a method can also be used in which an ultraviolet-curable paint is applied to the surface of the moving body, a stamper is pressed against the coating film, ultraviolet light is irradiated to cure the ultraviolet-curable paint, and the stamper is then peeled off to form an uneven shape. In this method, any stamper that transmits ultraviolet light can be used, for example, a resin stamper.

[0196] For example, in the case of a resin material, examples of the method include embossing such as single-sided embossing or double-sided embossing, laser processing, etc. For example, in the case of a ceramic material, examples of the method include laser processing, etc.

[0197] (4) Location of the gas drag reduction structure As described above, the gas drag reduction structure is disposed in front of the structure with respect to the traveling direction of the moving body. Also, as described above, the gas drag reduction structure is disposed only behind the position of the structure on the surface on which the structure is disposed with respect to the traveling direction of the moving body.

[0198] In addition to the front part of the structure, the gas resistance reduction structure is preferably located on the outer periphery of the moving body when viewed from the front, at the front part of the outer periphery based on the direction of travel of the moving body. The front part of the outer periphery is the part that is hit by the gas flow when the moving body travels. Therefore, flow separation is likely to occur at the front part of the outer periphery. Therefore, by arranging the gas resistance reduction structure at the front part of the outer periphery, the gas resistance reduction effect can be enhanced. It is sufficient that the gas resistance reduction structure is located at at least a part of the front part of the outer periphery.

[0199] As described above, in order to reduce gas resistance, the corners of a moving body that are the boundary between the front surface and the top surface of the moving body, the corners of the boundary between the front surface and the side surface of the moving body, and the corners of the boundary between the front surface and the bottom surface of the moving body are often rounded. In this case, the moving body has a flat portion from the top surface of the moving body toward the front surface, and a curved portion located in front of the flat portion and connecting to the flat portion. Similarly, the moving body has a flat portion from the side surface of the moving body toward the front surface, and a curved portion located in front of the flat portion and connecting to the flat portion. When the gas resistance reduction structure is disposed in the front portion of the outer periphery, the gas resistance reduction structure may be disposed across the flat portion and the curved portion of the moving body, or may be disposed only in the flat portion of the moving body, or may be disposed only in the curved portion of the moving body. Furthermore, flow separation is more likely near the point where the radius of curvature changes in the front portion of the outer periphery. Therefore, among the above, it is preferable that the gas resistance reduction structure be disposed in the front portion of the outer periphery, at least in the curved portion of the moving body. That is, it is preferable that the gas drag reduction structure is disposed so as to straddle the point where the radius of curvature changes in the front part of the outer circumferential portion. By disposing the gas drag reduction structure in this manner, flow separation can be effectively suppressed.

[0200] Furthermore, when the gas resistance reduction structure is positioned at the front of the outer peripheral portion, it is preferable that the gas resistance reduction structure is positioned at least at a corner that is the boundary between the front and top surfaces of the moving body, or at a corner that is the boundary between the front and side surfaces of the moving body.

[0201] In the bus 50 (mobile body) shown in Figures 4(a) to 4(c) and Figures 6(a) to 6(b), the gas resistance reduction structure 1 is arranged in the outer periphery 21 when the bus 50 (mobile body) is viewed from the front, in a part of the front part of the side of the bus 50 (mobile body), i.e., in a part of the front side of the bus 50.

[0202] Furthermore, in the truck 60 (mobile body) shown in Figures 5(a) to 5(b) and Figures 7(a) to 7(b), the gas resistance reduction structure 1 is arranged in the outer peripheral portion located on the outer periphery 21 when the truck 60 (mobile body) is viewed from the front, in part of the front part of the side of the truck 60 (mobile body), i.e., in part of the front side of the cabin 61 and part of the front side of the loading platform 62.

[0203] 5(a) and 5(b), the front side of the loading platform 62 includes both a portion corresponding to the front of the loading platform 62 (structure 20) and a portion other than the front of the loading platform 62 (structure 20) that is an outer peripheral portion disposed on the outer periphery when the truck 60 (mobile body) is viewed from the front and corresponds to the front of the outer peripheral portion. Specifically, the portion of the front side of the loading platform 62 that corresponds to the height H10 of the loading platform 62 (structure 20) corresponds to the front of the loading platform 62 (structure 20). Furthermore, the portion of the front side of the loading platform 62 that is other than the portion corresponding to the height H10 of the loading platform 62 (structure 20) and that is disposed on the outer periphery when the truck 60 (mobile body) is viewed from the front is a portion other than the front of the loading platform 62 (structure 20) that corresponds to the front of the outer peripheral portion.

[0204] In addition to the front of the structure, the gas resistance reduction structure may be disposed at least one of a corner at the boundary between the rear and side surfaces of the moving body, or a corner at the boundary between the rear and top surfaces of the moving body. Flow separation is likely to occur at these corners. Therefore, by disposing the gas resistance reduction structure at these corners, the gas resistance reduction effect can be enhanced.

[0205] 4. Other points In the present disclosure, gas resistance can be reduced. The gas is not particularly limited. The density of the gas is, for example, 0.08 kg / m 3 More than 10kg / m 3 The following is preferable: Among these, the gas is preferably air.

[0206] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any embodiment that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included within the technical scope of the present disclosure. [Example]

[0207] [Reference example 1] A pattern was printed on a printing stock (MPI1105) manufactured by Avery Dennison, and a laminate film (DOL1460) manufactured by Avery Dennison was laminated on top of it. Specifically, a printing stock ("MPI1105" manufactured by Avery Dennison) having a vinyl chloride resin film, an adhesive layer, and a release paper in this order was first used, and a pattern was printed on the vinyl chloride resin film of the printing stock to form a printed layer. Next, a laminate film ("DOL1460" manufactured by Avery Dennison) having a vinyl chloride resin film, an adhesive layer, and a release paper in this order was used, and after the release paper was peeled off the laminate film, the laminate film was laminated on the printed layer.

[0208] Next, a UV-curable ink (Seikabeam HT509, manufactured by Dainichiseika Chemicals Co., Ltd.) was ejected and cured using a UV inkjet device onto the laminate film, i.e., onto the vinyl chloride resin film of the laminate film, to form a first region having multiple linear convex and concave portions. The first region was formed so that the first and second regions were alternately arranged in a striped pattern, as shown in Figure 1(a). This resulted in the production of a film-like gas resistance reduction structure. The size of the film-like gas resistance reduction structure was 210 mm x 297 mm. Details of the gas resistance reduction structure are shown in Table 1.

[0209] [Rating 1] A truck-shaped model was used, measuring 1250 mm in length, 260 mm in width, and 387 mm in height, as shown in Figures 21(a) to 21(c). Figure 21(a) is a top view of the model, Figure 21(b) is a side view of the model, and Figure 21(c) is a rear view of the model. This truck-shaped model is a simple model that is 1 / 10 the size of a 10-ton truck. A film-like gas drag reduction structure was attached to the front side and front upper part of the truck-shaped model. A wind tunnel experiment was conducted under the following conditions, and the air drag coefficient (Cd value) was measured.

[0210] <Wind tunnel test conditions> Outlet dimensions: Rectangular, 1.0m wide and 0.7m high Measurement section length: 1.45m ·Wind speed: 25m / s Placement: Front side and front top of truck model -Attachment method: A film-like gas drag reduction structure was attached to the truck-shaped model, starting from the front R starting point and extending rearward.

[0211] The Cd value was calculated using the following formula. Cd=D / (ρU 2 S×1 / 2) (In the above formula, D: drag (N), ρ: density (kg / m 3 ), U: Representative speed (m / s), S: Representative area (m 2 ) In this experiment, the drag force D was measured using a load cell with a wire attached to a truck-shaped model. The density ρ was 1.124 kg / m 3 , the representative speed U is the same as the wind speed, and the representative area S is 0.101m 2 It was decided.

[0212] In addition, Comparative Example 1 was a case where no film-like gas resistance reducing structure was attached.

[0213] [Table 1]

[0214] [Reference example 2] A printing stock (3M's "IJ180 mc-114") with a transparent substrate was used. A laminate film (Avery Dennison's "DOL1460Z") was used, consisting of a vinyl chloride resin film, an adhesive layer, and a release paper, in that order. After peeling the release paper from the laminate film, the laminate film was laminated onto the printing stock. Next, a UV-curable ink (Dainichiseika Chemicals' "Seikabeam HT509") was ejected and cured on the vinyl chloride resin film of the laminate film using a UV inkjet device to form a first region with multiple linear convex and concave portions. The first region was formed so that the first and second regions were alternately arranged in a striped pattern, as shown in Figure 1(a). This resulted in the production of a film-like gas resistance reduction structure. The size of the film-like gas resistance reduction structure was 210 mm × 297 mm. Details of the gas resistance reduction structure are shown in Table 1.

[0215] [Rating 2] The Cd value was measured in the same manner as in Evaluation 1, except that the following wind tunnel test conditions were used.

[0216] <Wind tunnel test conditions> Outlet dimensions: Rectangular, 1.0m wide and 0.7m high Measurement section length: 1.45m ·Wind speed: 5 levels: 10m / s, 15m / s, 20m / s, 25m / s, 30m / s Film size: 210mm x 297mm Placement: Front side and front top of truck model - Application method: The film was applied from the front R starting point of the truck-shaped model toward the rear.

[0217] In addition, Comparative Example 2 was a case where no film-like gas resistance reducing structure was attached.

[0218] [Table 2]

[0219] [Reference example 3] Film-like gas drag reduction structures were produced in the same manner as in Reference Example 1. The film-like gas drag reduction structures had dimensions of 387 mm × 210 mm, 387 mm × 630 mm, and 387 mm × 1050 mm. The width of the first region was 5 mm, the width of the second region was 5 mm, the length of the first region was 210 mm, 630 mm, or 1050 mm, the height of the convex portions of the first region was 150 μm, the width of the convex portions of the first region was 100 μm, and the width of the concave portions of the first region was 700 μm.

[0220] [Rating 3] The same truck-shaped model as in Evaluation 1 was used. A film-like gas drag reduction structure was attached to both sides of the truck-shaped model so that the 387 mm long sides were vertical. A wind tunnel experiment was conducted under the following conditions, and the Cd value was measured.

[0221] <Wind tunnel test conditions> Outlet dimensions: Rectangular, 1.0m wide and 0.7m high Measurement section length: 1.45m ·Wind speed: 5 levels: 10m / s, 15m / s, 20m / s, 25m / s, 30m / s Placement: On both sides of the truck model - Attachment method: Starting from the rear end of the loading platform of the truck-shaped model, a film-like gas drag reduction structure was attached toward the front.

[0222] In addition, Comparative Example 3 was a case where no film-like gas resistance reducing structure was attached.

[0223] [Table 3]

[0224] Tables 1 and 2 show that when film-type gas drag reduction structures were attached to the front side and upper front of the truck-shaped model, the Cd value was smaller than when no film-type gas drag reduction structures were attached. On the other hand, Table 3 shows that when film-type gas drag reduction structures were attached to both side surfaces of the truck-shaped model, the Cd value was larger than when no film-type gas drag reduction structures were attached. These results confirm that placing gas drag reduction structures on corners where flow separation occurs results in a gas drag reduction effect, whereas placing gas drag reduction structures on flat areas where flow separation is less likely to occur does not result in a gas drag reduction effect. This suggests that gas drag reduction structures can increase frictional resistance. Furthermore, while the truck-shaped model does not have any structures, the presence of structures on the moving vehicle suggests that the structures can act as obstacles and insufficiently suppress the reduction in gas flow velocity.

[0225] The present disclosure provides the following inventions. [1] A moving body having a gas drag reduction structure on a surface thereof, the gas drag reduction structure has a first region having an uneven structure and a second region adjacent to the first region, the first region and the second region extending in a band shape in the traveling direction of the moving body, a structure is arranged on the outer periphery of the moving body when viewed from the front, the gas drag reduction structure is disposed in a front portion of the structure with respect to a traveling direction of the moving body; the gas resistance reduction structure is arranged only behind the position of the structure on the surface on which the structure is arranged, with respect to the traveling direction of the moving object; A moving body, wherein the height of the structure is greater than the boundary layer thickness of the moving body. [2] The moving body described in [1], wherein the gas drag reduction structure is disposed in a peripheral portion that is disposed on the outer periphery of the moving body when viewed from the front, and in a front portion of the peripheral portion based on the direction of travel of the moving body. [3] The moving body according to [1] or [2], wherein in the gas resistance reduction structure, the first regions and the second regions are alternately arranged in a direction intersecting the traveling direction of the moving body. [4] the height of the convex portions of the concave-convex structure in the first region is 1.1 μm or more and 1000 μm or less; The length of the first region in the traveling direction of the moving body is 30 mm or more, A moving body according to any one of [1] to [3], wherein the width of the first region and the width of the second region in a direction intersecting the direction of travel of the moving body are 0.2 mm or more and 50 mm or less. [Explanation of symbols]

[0226] 1. Gas drag reduction structure 2 … 1st area 3 … Second area 10 … uneven structure 11... Convex part 12 ... recess 20 … structure 50... Bus (mobile) 60... Truck (mobile) D1: Direction of travel of the moving object D2: Direction that intersects with the direction of travel of the moving object H10: Height of the structure

Claims

1. A moving body having a gas drag reduction structure on a surface thereof, the gas drag reduction structure has a first region having a concave-convex structure and a second region adjacent to the first region, the first region and the second region extending in a band shape in a traveling direction of the moving body, a structure is disposed on the outer periphery of the moving body when viewed from the front, the gas drag reduction structure is disposed in a front portion of the structure with respect to a traveling direction of the moving body, the gas resistance reduction structure is disposed only behind the position of the structure on the surface on which the structure is disposed, with respect to the traveling direction of the moving object; A moving body, wherein the height of the structure is greater than the boundary layer thickness of the moving body.

2. 2. The moving body according to claim 1, wherein the gas resistance reducing structure is disposed in an outer peripheral portion that is disposed on the outer periphery of the moving body when viewed from the front, and in a front portion of the outer peripheral portion with respect to the direction of travel of the moving body.

3. The moving body according to claim 1 , wherein in the gas resistance reduction structure, the first regions and the second regions are alternately arranged in a direction intersecting a traveling direction of the moving body.

4. the height of the convex portions of the concave-convex structure in the first region is 1.1 μm or more and 1000 μm or less; The length of the first region in the traveling direction of the moving body is 30 mm or more, 2. The moving body according to claim 1, wherein the width of the first region and the width of the second region in a direction intersecting the traveling direction of the moving body are 0.2 mm or more and 50 mm or less.

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