Peeling suppression device

Abstract

To reduce the pressure resistance on the outer surface of the moving object. [Solution] The peeling suppression device 30 is provided on the upper surface 211 of the spoiler and suppresses the separation of airflow. The peeling suppression portion 31 of the peeling suppression device 30 includes a pair of protruding portions 32, 33 that are spaced apart in the vehicle width direction Y, and a recessed groove portion 34 that is provided in a position sandwiched between the pair of protruding portions 32, 33. The protruding portions 32, 33 are shaped to protrude from the upper surface 211 of the spoiler and become narrower towards the protruding end, forming a protrusion that extends in the front-rear direction X. The recessed groove portion 34 is shaped to be recessed from the upper surface 211 of the spoiler and becomes narrower towards the bottom, forming a recessed groove that extends in the front-rear direction X. The coefficient of friction Cf between the upper surface 211 of the spoiler and the air flowing along the upper surface 211 of the spoiler is used, and the distance W1 between the pair of protrusions 32 and 33 is determined according to the coefficient of friction Cf near the peeling suppression portion 31 on the upper surface 211 of the spoiler.

Description

Technical Field

[0001] The present invention relates to a peeling suppression device.

Background Art

[0002] Conventionally, in the peeling suppression device described in Patent Document 1, for example, when applied to a vehicle, a plurality of convex portions much smaller than the boundary layer thickness of the flow are provided at the rear end portion of the roof so as to be arranged at intervals in the vehicle width direction.

[0003] In this device, the convex portions control the flow of air (airflow) along the outer surface of the vehicle during running. As a result, the peeling of the airflow in the vicinity of the rear end portion of the roof of the vehicle, specifically, the rear window, is suppressed, and thus the air resistance of the vehicle is reduced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Here, in each part of the outer surface of the vehicle, the state of the above airflow is not uniform. Therefore, even if convex portions are simply provided on the outer surface of the vehicle, it is not always possible to appropriately control the airflow in the portion where the convex portions are provided. The peeling suppression device described in Patent Document 1 has room for improvement in this regard.

[0006] In addition, the actual situation regarding the control of the airflow by such convex portions is not limited to the case where the convex portions are provided on a vehicle, and is generally common even when the convex portions are provided on a moving body other than a vehicle, such as a ship or an aircraft.

Means for Solving the Problems

[0007] The following describes various embodiments of a peeling suppression device for solving the above problems. [Aspect 1] A peeling suppression device provided on the outer surface of a moving body to suppress the separation of fluid flow along the outer surface, the peeling suppression device having a pair of protruding portions arranged at intervals in an intersecting direction that intersects the front-rear direction when the moving body is moving, and a recessed portion provided at a position sandwiched between the pair of protruding portions, wherein the protruding portions have a shape in which the outer surface protrudes and becomes narrower towards the tip, forming a protrusion that extends in the front-rear direction, and the recessed portion has a shape in which the outer surface is recessed and becomes narrower towards the bottom, forming a recessed groove that extends in the front-rear direction, and the spacing between the pair of protruding portions is determined according to the wall friction coefficient between the outer surface and the fluid flowing along the outer surface and the wall friction coefficient near the peeling suppression portion on the outer surface.

[0008] With the above configuration, a longitudinal vortex that swirls clockwise when viewed from the rear (hereinafter referred to as the first vortex) can be generated by utilizing the outer surface of one protruding section and the inner surface of the groove section continuous with that outer surface. Furthermore, a longitudinal vortex that swirls counterclockwise when viewed from the rear (hereinafter referred to as the second vortex) can be generated by utilizing the outer surface of the other protruding section and the inner surface of the groove section continuous with that outer surface. In this way, by providing a separation suppression section, two vortex flows with different winding directions can be generated.

[0009] Furthermore, by setting the distance between the pair of protrusions to a value corresponding to the coefficient of friction of the wall surface near the separation suppression section on the outer surface of the moving body, it can be determined based on the ordered structure of the fluid that is amplified to the maximum extent, according to fluid dynamics theory. As a result, it is possible to generate vortices that are appropriately strong in suppressing fluid flow separation as the first and second vortices.

[0010] Furthermore, these vortices can generate turbulence, allowing energy from the turbulence to be supplied as momentum near the outer surface of the moving object. This suppresses the separation of the fluid (more specifically, the flow) along the outer surface of the moving object, thereby reducing the pressure resistance against the outer surface of the moving object.

[0011] [Aspect 2] The peeling suppression device according to [Aspect 1], wherein a plurality of peeling suppression units are provided so as to be arranged in the intersecting direction, and the structure in which the spacing between them is determined according to the coefficient of friction of the wall surface is applied separately to each of the plurality of peeling suppression units.

[0012] According to the above configuration, two vortices can be generated in a manner suitable for suppressing fluid flow separation in various parts of the outer surface of the moving body, more specifically in the parts where any of the separation suppression parts are provided. As a result, fluid flow separation can be suppressed over a wide area of ​​the outer surface of the moving body, and thus the pressure resistance against the outer surface of the moving body can be suitably reduced.

[0013] [Aspect 3] The peeling suppression device according to [Aspect 1] or [Aspect 2], wherein, assuming that the peeling suppression part is not provided, the surface constituting the outer surface is considered a reference surface, the interval is the interval on the reference surface.

[0014] According to the above configuration, the spacing between the pair of protrusions can be determined to match the shape of the outer surface of the moving body (more specifically, the reference surface) so that fluid flow separation is properly suppressed. [Aspect 4] The peeling suppression device according to any one of [Aspect 1] to [Aspect 3], wherein the bottom of the groove portion is provided with a protruding bottom surface of the groove portion and a shape that narrows towards the tip, and a protrusion extending in the front-rear direction.

[0015] According to the above configuration, a first vortex can be generated by the outer surface of one ridge portion, the inner surface of the concave groove portion, and one side surface of the convex portion, and a second vortex can be generated by the outer surface of the other ridge portion, the inner surface of the concave groove portion, and the other side surface of the convex portion. Thus, since the portion for generating the first vortex and the portion for generating the second vortex in one peeling suppression portion can be separated by the convex portion, the first vortex and the second vortex can be accurately generated in desired modes respectively.

[0016] [Aspect 5] The peeling suppression portion is a portion having a positive pressure gradient on the outer surface, and is arranged in a portion where the positive pressure gradient increases as it goes rearward in the front-rear direction. The peeling suppression device according to any one of [Aspect 1] to [Aspect 4].

[0017] According to the above configuration, since a peeling suppression portion can be provided in a portion where there is a possibility of airflow peeling at the rear among each part of the outer surface of the moving body, the peeling suppression portion can accurately suppress the occurrence of peeling at the rear thereof.

[0018] [Aspect 6] The moving body is a vehicle having a rear spoiler, the fluid is air, and the peeling suppression portion is provided on the upper surface of the rear spoiler. The peeling suppression device according to any one of [Aspect 1] to [Aspect 5].

[0019] According to the above configuration, the peeling of the airflow flowing along the upper surface of the vehicle including the upper surface of the rear spoiler can be suppressed. Therefore, the air resistance of the vehicle during running can be suppressed.

Effect of the Invention

[0020] According to the present invention, the pressure resistance against the outer surface of the moving body can be reduced.

Brief Description of the Drawings

[0021] [Figure 1]FIG. 1 is a side view of a vehicle to which the peeling suppression device according to one embodiment is applied. [Figure 2] FIG. 2 is a side view showing the rear spoiler of the vehicle and its surroundings. [Figure 3] FIG. 3 is a plan view of the rear spoiler of the vehicle. [Figure 4] FIG. 4 is a perspective view of the peeling suppression device according to the embodiment as viewed obliquely from above. [Figure 5] FIG. 5 is a view of the upper surface of the peeling suppression portion according to the embodiment as viewed from the rear side. [Figure 6] FIG. 6 is a view of the upper surface of the peeling suppression portion according to the embodiment as viewed from the rear side. [Figure 7] FIG. 7 is a view of the upper surface of the peeling suppression portion according to the embodiment as viewed from the left side. [Figure 8] FIG. 8 is a view of the upper surface of the peeling suppression portion according to the embodiment as viewed from the left side. [Figure 9] FIG. 9 is a view of the upper surfaces of a plurality of the peeling suppression portions as viewed from the rear side. [Figure 10] FIG. 10 is an image showing the results of simulations performed by the inventors. [Figure 11] FIG. 11 is an explanatory diagram for explaining the operation of the peeling suppression device according to the embodiment. [Figure 12] FIG. 12 is a view of the upper surface of the peeling suppression portion of a modification as viewed from the rear side. [Figure 13] FIG. 13 is a view of the upper surface of the peeling suppression portion of another modification as viewed from the rear side. [Figure 14] FIG. 14 is a view of the upper surface of the peeling suppression portion of another modification as viewed from the rear side.

MODE FOR CARRYING OUT THE INVENTION

[0022] Hereinafter, an embodiment of the peeling suppression device will be described with reference to FIGS. 1 to 11. As shown in Figure 1, the peeling suppression device 30 of this embodiment is applied to a vehicle 20 such as an automobile. In the following explanation, the longitudinal direction when the vehicle 20 is moving (more specifically when moving straight) will be referred to as the longitudinal direction X, the vehicle width direction as the vehicle width direction Y, and the vertical direction of the vehicle 20 when the vehicle 20 is positioned on a horizontal plane as the vertical direction Z. Furthermore, the front and rear sides in the longitudinal direction X will be simply referred to as "front side" and "rear side," respectively, the right and left sides in the vehicle width direction Y will be simply referred to as "right side" and "left side," respectively, and the upper and lower sides in the vertical direction Z will be simply referred to as "upper side" and "lower side," respectively.

[0023] Vehicle 20 has a rear spoiler 21. The rear spoiler 21 is mounted on the rear of vehicle 20, specifically behind the roof 22. The upper surface of the rear spoiler 21 (hereinafter referred to as the spoiler upper surface 211) constitutes a part of the upper surface of vehicle 20 (hereinafter referred to as the vehicle upper surface 201).

[0024] As shown in Figure 2, in the vehicle 20, the rear end portion of the upper surface of the roof 22 (hereinafter referred to as the roof upper surface 221) and the front end portion of the spoiler upper surface 211 are sloped downwards towards the rear. Furthermore, at the boundary portion between the rear end portion of the roof 22 and the front end portion of the rear spoiler 21 (hereinafter referred to as the boundary portion 23), the curvature of the vehicle upper surface 201 is greater compared to the portions before and after it. Specifically, the vehicle upper surface 201 is curved upwards in a convex shape at the boundary portion 23. Due to this shape of the vehicle upper surface 201, when the vehicle 20 is traveling forward, the pressure gradient becomes "positive" in the rear region of the boundary portion 23 on the vehicle upper surface 201. This rear region includes the front end portion of the spoiler upper surface 211. Also, due to the above shape, in the region of the rear region adjacent to the boundary portion 23, i.e., the front end portion of the spoiler upper surface 211, the positive pressure gradient increases as the vehicle 20 moves towards the rear.

[0025] As shown in Figures 1 to 3, the peeling suppression device 30 of this embodiment is provided on the front end portion of the spoiler upper surface 211. More specifically, the peeling suppression device 30 is provided such that its front end is located behind the front end of the spoiler upper surface 211. In other words, the peeling suppression device 30 is located on the outer surface of the vehicle 20 in a portion that has a positive pressure gradient, and the positive pressure gradient increases towards the rear of the vehicle 20.

[0026] As shown in Figures 4 to 8, the peeling suppression device 30 has a plurality of peeling suppression parts 31. The plurality of peeling suppression parts 31 are arranged in a line with spacing between them in an intersecting direction (in this embodiment, the vehicle width direction Y) that intersects the front-rear direction X. In this embodiment, each peeling suppression part 31 is provided at the front end portion of the spoiler upper surface 211. More specifically, each peeling suppression part 31 is molded integrally with the rear spoiler 21 so as to constitute a part of the upper wall of the rear spoiler 21. The peeling suppression device 30 suppresses the peeling of the airflow flowing along the spoiler upper surface 211.

[0027] <Peeling suppression section 31> The basic structure of the peeling suppression unit 31 will be described below. As shown in Figures 4 to 6, the peeling suppression portion 31 has a pair of protruding portions 32 and 33, a groove portion 34, and a protruding portion 35.

[0028] <Pair of protruding parts 32, 33> The pair of protrusions 32 and 33 are composed of a first protrusion 32 located on the left side and a second protrusion 33 located on the right side. The first protrusion 32 and the second protrusion 33 have the same outer surface shape. The first protrusion 32 and the second protrusion 33 are arranged with a gap W1 between them in the intersecting direction (in this embodiment, the vehicle width direction Y) that intersects the front-rear direction X.

[0029] As shown in Figures 4 to 8, each of the protruding sections 32 and 33 has a shape in which the spoiler upper surface 211 protrudes. Each of the protruding sections 32 and 33 is a protrusion extending in the front-rear direction X. The outer surface shape of each of the protruding sections 32 and 33 is narrower towards the tip. The outer surface shape of each of the protruding sections 32 and 33 is wider towards the center in the front-rear direction X from the front end, with the width being maximum at the center in the front-rear direction X, and narrower towards the rear end in the section from the center in the front-rear direction X to the rear end. Figures 5 to 8 show the cross-sectional shape of the outer surface of the peeling suppression section 31 at the center in the front-rear direction X.

[0030] As shown in Figures 7 and 8, the projection height H1 of the protruding portions 32 and 33 from the reference surface 24 increases towards the center in the portion from the front end to the center in the longitudinal direction X, and decreases towards the rear end in the portion from the center in the longitudinal direction X to the rear end. The projection height H1 is maximum at the center of the protruding portions 32 and 33 in the longitudinal direction X. The reference surface 24 is the surface that constitutes the outer surface of the rear spoiler 21, assuming that the peeling suppression portion 31 is not provided.

[0031] <Concave groove part 34> As shown in Figures 4 to 6, the groove portion 34 is positioned between a pair of protruding portions 32 and 33 in the vehicle width direction Y.

[0032] As shown in Figures 4 to 8, the groove portion 34 has a shape in which the spoiler upper surface 211 is recessed. The groove portion 34 is a groove shape that extends in the front-rear direction X. The inner surface shape of the groove portion 34 is narrower towards the bottom 341. Furthermore, the inner surface shape of the groove portion 34 is narrower towards the center from the front end to the center in the front-rear direction X, with the width being smallest at the center in the front-rear direction X, and wider towards the rear end from the center in the front-rear direction X to the rear end.

[0033] As shown in Figures 7 and 8, the depth H2 of the groove 34 from the reference surface 24 increases towards the center in the portion from the front end to the center in the longitudinal direction X, and decreases towards the rear end in the portion from the center in the longitudinal direction X to the rear end. The depth H2 is maximum at the center of the groove 34 in the longitudinal direction X.

[0034] <Protrusion 35> As shown in Figures 4 to 6, the protrusion 35 is provided on the bottom 341 of the groove 34. The protrusion 35 has a shape that protrudes from the bottom 341 of the groove 34. The protrusion 35 extends in the front-rear direction X at the center in the width direction of the groove 34. The outer shape of the protrusion 35 is narrower towards the tip. The upper surface of the protrusion 35 (hereinafter, the upper surface 351 of the protrusion) extends on the same plane as the reference surface 24 and extends with the same width in the front-rear direction X. The distance between the two sides of the protrusion 35 decreases towards the center in the portion from the front end to the center in the front-rear direction X, becoming the minimum at the center in the front-rear direction X, and increases towards the rear end in the portion from the center in the front-rear direction X to the rear end. The height of the protrusion 35 from the bottom 341 of the groove 34 is equal to the depth H2 of the groove 34 from the reference surface 24 (see Figures 7 and 8). Therefore, the height of the protrusion 35 from the bottom 341 of the groove 34 increases towards the center in the portion from the front end of the protrusion 35 to the center in the front-rear direction X, and decreases towards the rear end in the portion from the center in the front-rear direction X to the rear end. The height of the protrusion 35 is maximum at the center in the front-rear direction X.

[0035] In this embodiment, the peeling suppression portion 31 is composed of a pair of protruding portions 32 and 33, a groove portion 34, and a convex portion 35. Figures 5 and 7 show the outer surface shape of the peeling suppression portion 31 in the portion where the reference surface 24 is a flat surface. In contrast, Figures 6 and 8 show the outer surface shape of the peeling suppression portion 31 in the portion where the reference surface 24 is an arc-shaped surface. In this embodiment, as shown in example Figures 6 and 8, in the portion where the reference surface 24 is not a flat surface, the pair of protruding portions 32 and 33, the groove portion 34, and the convex portion 35 constituting the peeling suppression portion 31 are provided to extend along the reference surface 24.

[0036] As shown in Figures 5 and 6, in this embodiment, the series of surfaces connecting the right outer surface of the first protrusion 32, the left inner surface of the groove 34, and the left outer surface of the convex portion 35 are made of smooth surfaces that do not form steps at the boundaries, such as surfaces with a sinusoidal cross-section. Similarly, the series of surfaces connecting the left outer surface of the second protrusion 33, the right inner surface of the groove 34, and the right outer surface of the convex portion 35 are also made of smooth surfaces that do not form steps at the boundaries, such as surfaces with a sinusoidal cross-section.

[0037] In this embodiment, in order to effectively suppress airflow separation on the spoiler upper surface 211, the distance W1 (Figure 5) between the pair of protrusions 32 and 33 in the separation suppression section 31 is determined according to the wall friction coefficient Cf between the vehicle upper surface 201 and the air flowing along the vehicle upper surface 201. In this embodiment, when determining the distance W1 in this way, the wall friction coefficient Cf used is the wall friction coefficient near the separation suppression section 31 on the vehicle upper surface 201. Specifically, the wall friction coefficient Cf used is the portion in front of the separation suppression section 31 (more precisely, the front end of the spoiler upper surface 211), that is, the portion located in front of the separation suppression section 31.

[0038] In this embodiment, the interval W1 is the interval on the reference surface 24. For example, in the example shown in Figure 6, the interval W1 is the length of the line traced along the reference surface 24 from point A to point B.

[0039] In this embodiment, the structure for setting the interval W1 according to the wall friction coefficient Cf is applied separately to each of the multiple peeling suppression sections 31 that constitute the peeling suppression device 30. Therefore, in this embodiment, as shown in Figure 9, the interval W1 is non-uniform in the multiple peeling suppression sections 31. In this embodiment, the multiple peeling suppression sections 31 include four types with different intervals W1. Specifically, the multiple peeling suppression sections 31 include peeling suppression section 31A with interval W1 "A", peeling suppression section 31B with interval W1 "B", peeling suppression section 31C with interval W1 "C", and peeling suppression section 31D with interval W1 "D".

[0040] In this embodiment, a peeling suppression section 31 is provided on the spoiler upper surface 211 in order to create a streak structure on the spoiler upper surface 211. When the streak structure appears, high-speed regions with high airflow velocity and low-speed regions with low airflow velocity alternate in the vehicle width direction Y on the spoiler upper surface 211. In this case, the period λy during which a set of adjacent regions consisting of one high-speed region and one low-speed region appears changes according to the wall friction coefficient Cf of the spoiler upper surface 211.

[0041] The inventors of the present invention have obtained the following finding: By matching the above period λy with the above interval W1, the separation suppression section 31 can create a streak structure on the spoiler upper surface 211 in a manner suitable for suppressing airflow separation.

[0042] In this embodiment, the period λy is determined based on the wall friction coefficient Cf, and this period λy is set to the distance W1 between the pair of protrusions 32 and 33. As a result, a streak structure appears in each part of the spoiler upper surface 211, i.e., in the parts where each separation suppression part 31 is provided, in a manner suitable for suppressing airflow separation.

[0043] The wall friction coefficient Cf at each part of the front end of the spoiler upper surface 211 can be determined, for example, based on the results of a simulation. In this embodiment, the wall friction coefficient Cf at each part is determined based on the results of a simulation performed by the inventors (specifically, fluid analysis using computational fluid dynamics (CFD)).

[0044] Figure 10 shows the results of a simulation performed by the inventors. The simulation results yielded a color image showing the magnitude of the wall friction coefficient Cf at various parts of the vehicle's upper surface 201, including the spoiler upper surface 211, using the displayed color and its intensity. Figure 10 shows this color image converted to a grayscale image. As is clear from Figure 10, the wall friction coefficient Cf has a distribution at the front end of the spoiler upper surface 211 (indicated by the white arrow in the figure). In this embodiment, the spacing W1 between the pair of protrusions 32 and 33 in the peeling suppression section 31 is set according to this wall friction coefficient Cf.

[0045] The spacing W1 between the pair of protrusions 32 and 33 can be calculated as follows. Specifically, the period λy can be determined based on the wall friction coefficient Cf, air density ρ, air velocity U, and air kinematic viscosity coefficient ν, which correspond to the area on the spoiler upper surface 211 where the peeling suppression portion 31 is to be placed. This period λy can then be set as the spacing W1.

[0046] Specifically, for example, the period λy can be determined using the following relationships (1) to (3), based on the wall friction coefficient Cf, air density ρ, air velocity U, and air kinematic viscosity ν.

[0047] (Cf) = (Tw) / [(1 / 2) × (ρ) × "(U) squared"] ... (1) (Tw) = (ρ) × [(Ut) squared] ... (2) (λy+)=(λy)×(Ut) / (ν)…(3) In relation (1), (Tw) is the shear stress, and in relation (3), (λy+) is a dimensionless number and (Ut) is the friction velocity. When using the above relations (1) to (3) to find the period λy, it is preferable to set the dimensionless number "λy+" to "100".

[0048] <Operation and Effects of This Embodiment> The operation and effects of this embodiment will be described below. As shown in Figure 11, the left portion of the outer surface of the peel-inhibiting section 31 is composed of a series of surfaces connected to the right outer surface of the first protrusion 32, the left inner surface of the groove 34, and the left outer surface of the convex section 35. The right outer surface of the first protrusion 32 and the left inner surface of the groove 34 form a surface that slopes downward to the right, and the left outer surface of the convex section 35 that follows forms a surface that slopes upward to the right.

[0049] Furthermore, the right portion of the outer surface of the peel-inhibiting section 31 is composed of a series of surfaces connected to the left outer surface of the second protrusion 33, the right inner surface of the groove 34, and the right outer surface of the convex section 35. The left outer surface of the second protrusion 33 and the right inner surface of the groove 34 form a surface that slopes downward to the left, and the right outer surface of the convex section 35 that follows forms a surface that slopes upward to the left.

[0050] In this embodiment, a portion of the air flowing along the spoiler upper surface 211 flows along the left portion of the outer surface of the peel-inhibiting section 31, or along the right portion of the outer surface of the same section, thereby forming an airflow near the spoiler upper surface 211 that includes a component directed in the vertical direction Z. More specifically, an airflow DF including a downward component is formed above the portion of the peel-inhibiting section 31 that is in the center in the vehicle width direction Y. In addition, an upward airflow UF is formed above the portions of the peel-inhibiting section 31 that are on both sides in the vehicle width direction Y.

[0051] These airflows DF and UF induce two longitudinal vortices (first vortex flow FV1 and second vortex flow FV2). Specifically, the first vortex flow FV1, which is a longitudinal vortex that swirls clockwise when viewed from the rear, is induced in the upper left of the separation suppression section 31. The second vortex flow FV2, which is a longitudinal vortex that swirls counterclockwise when viewed from the rear, is induced in the upper right of the separation suppression section 31.

[0052] In this way, by providing the separation suppression section 31, two vortex flows FV1 and FV2 can be generated. Furthermore, turbulence can be generated by the two vortex flows FV1 and FV2. Moreover, since two vortex flows FV1 and FV2 with different winding directions are generated, the turbulent transition of the airflow flowing along the spoiler upper surface 211 is promoted compared to the case where only vortices with the same winding direction are generated.

[0053] As a result, turbulent energy is supplied as momentum to the vicinity of the spoiler's upper surface 211. This suppresses the separation of the airflow along the spoiler's upper surface 211. By suppressing airflow separation in this way, the pressure resistance on the vehicle's upper surface 201 is reduced, and therefore the air resistance of the vehicle 20 is reduced.

[0054] Furthermore, in this embodiment, the spacing W1 between the pair of protrusions 32 and 33 in the separation suppression section 31 is determined according to the wall friction coefficient Cf at the front end of the spoiler upper surface 211. This allows the spacing W1 to be determined based on the fluid order structure that maximizes amplification based on fluid dynamics theory. As a result, in the portion of the spoiler upper surface 211 where the separation suppression section 31 is provided, a streak structure appears in a manner suitable for suppressing airflow separation. At this time, the first vortex flow FV1 and the second vortex flow FV2 are generated to be appropriately strong enough to suppress airflow separation.

[0055] Furthermore, in this embodiment, a structure in which the above-mentioned interval W1 is determined according to the wall friction coefficient Cf is applied separately to each of the multiple separation suppression sections 31. As a result, a streak structure appears in a manner suitable for suppressing airflow separation in each part of the spoiler upper surface 211, more specifically in the parts where any of the multiple separation suppression sections 31 are provided. This suppresses airflow separation over a wide area of ​​the spoiler upper surface 211, thereby effectively reducing the air resistance of the vehicle 20.

[0056] The effects of this embodiment will be described below. (1) Since the separation of the airflow along the spoiler upper surface 211 can be suppressed, the pressure resistance on the vehicle upper surface 201 can be reduced. Moreover, since a streak structure can be created on the spoiler upper surface 211 in a manner suitable for suppressing airflow separation, the pressure resistance on the spoiler upper surface 211 can be suitably reduced. Therefore, the air resistance of the vehicle 20 can be suitably reduced.

[0057] (2) Multiple peeling suppression sections 31 are provided so as to be aligned in the vehicle width direction Y. The structure for setting the spacing W1 between a pair of protrusions 32, 33 according to the wall friction coefficient Cf is applied separately to each of the multiple peeling suppression sections 31. As a result, airflow separation is properly suppressed over a wide area of ​​the spoiler upper surface 211, and the pressure resistance of the spoiler upper surface 211 can be suitably reduced.

[0058] (3) Assuming that the peeling suppression section 31 is not provided, and the surface constituting the spoiler upper surface 211 is the reference surface 24, the interval W1 is the interval on the reference surface 24. According to the above configuration, the distance W1 between the pair of protrusions 32 and 33 can be determined to match the shape of the spoiler upper surface 211 (more specifically, the reference surface 24) so ​​that airflow separation is properly suppressed.

[0059] (4) The bottom 341 of the groove 34 is provided with a protruding portion 35 that extends in the front-rear direction X, with the bottom surface of the groove 34 protruding and becoming narrower towards the tip. With the above configuration, a first vortex flow FV1 can be generated by a series of connected surfaces: the right outer surface of the first protrusion 32, the left inner surface of the groove 34, and the left outer surface of the convex portion 35. Furthermore, a second vortex flow FV2 can be generated by a series of connected surfaces: the left outer surface of the second protrusion 33, the right inner surface of the groove 34, and the right outer surface of the convex portion 35. In this way, the convex portion 35 can separate the part that generates the first vortex flow FV1 and the part that generates the second vortex flow FV2 within a single peeling suppression portion 31. Therefore, the first vortex flow FV1 and the second vortex flow FV2 can be generated accurately in the desired manner.

[0060] (5) The peeling suppression device 30 is located in a portion of the outer surface of the vehicle 20 that has a positive pressure gradient, and in a portion where the positive pressure gradient increases towards the rear of the vehicle 20. According to the above configuration, the separation suppression section 31 can be provided in the rear portion of the vehicle's upper surface 201 where there is a risk of airflow separation occurring. Therefore, the separation suppression section 31 can effectively suppress the occurrence of airflow separation behind the vehicle.

[0061] (6) The separation suppression section 31 is provided on the upper surface 211 of the spoiler. Therefore, it is possible to suppress the separation of the airflow that flows along the upper surface 201 of the vehicle, including the upper surface 211 of the spoiler. Consequently, the air resistance of the vehicle 20 when the vehicle 20 is in motion can be reduced.

[0062] <Variation> The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0063] The spacing W1 between the pair of protrusions 32 and 33 can be arbitrarily changed as long as it is a value (spacing) corresponding to the wall friction coefficient Cf. For example, the spacing W1 can be set to a value slightly different from the period λy, or to a value twice the period λy (=[λy]×2). In short, the spacing W1 should be set to a value that allows a streak structure to appear on the spoiler upper surface 211 in a manner suitable for suppressing airflow separation.

[0064] The peeling suppression unit 31 may be provided by only one unit. In other words, the peeling suppression device 30 may be composed of only one peeling suppression unit 31. The upper surface 351 of the protrusion can be made to extend on the same plane as the reference surface 24, or it can be made to extend below the reference surface 24, or it can extend above the reference surface 24.

[0065] The distance between two adjacent peeling suppression sections 31 (for example, the distance shown as W2 in Figure 5) may be determined in accordance with the wall friction coefficient Cf, similar to the distance W1 between the pair of protruding sections 32 and 33. In this case, the wall friction coefficient Cf may be the wall friction coefficient in the vicinity of the portion between the two adjacent peeling suppression sections 31 on the upper surface 201 of the vehicle. Specifically, the wall friction coefficient Cf may be the wall friction coefficient in the portion in front of or behind the portion between the two peeling suppression sections 31.

[0066] As shown in Figure 12 as an example, a portion of the bottom surface of the groove 34 (such as the portion indicated by arrows E1 and E2 in the figure) may be made of a surface that extends linearly in the vehicle width direction Y. - In addition to arranging the first protrusion 32 and the second protrusion 33 of two adjacent peeling suppression parts 31 with a gap in the vehicle width direction Y, they may also be formed integrally, as shown in the example in Figure 13. In the example shown in Figure 13, the outer surface shapes of the first protrusion 32 and the second protrusion 33 are such that the tip of the first protrusion 32 and the tip of the second protrusion 33 are connected by a surface that extends linearly in the vehicle width direction Y.

[0067] As shown in Figure 14 as an example, the protrusion 35 (see Figure 5) may be omitted. Even in this configuration, one peeling suppression section 31 can induce two vortex flows FV1 and FV2 with different winding directions. Specifically, the first vortex flow FV1 can be generated by the downward-sloping surface formed by the right outer surface of the first protrusion 32 and the left inner surface of the groove 34. The second vortex flow FV2 can be generated by the downward-sloping surface formed by the left outer surface of the second protrusion 33 and the right inner surface of the groove 34.

[0068] The delamination suppression device 30 is not limited to being located in a portion of the vehicle's upper surface 201 that has a positive pressure gradient and where the positive pressure gradient increases towards the rear of the vehicle 20 (hereinafter referred to as the "positive portion"), but can be located in any portion of the vehicle's upper surface 201. For example, the delamination suppression device 30 can be located in a position that includes a portion of the vehicle's upper surface 201 that is in front of the aforementioned positive portion, or in a position that includes a portion of the vehicle's upper surface 201 that is in rear of the aforementioned positive portion. In addition, the delamination suppression device 30 can be located in a position that is in front of the aforementioned positive portion, or in a position that is in rear of the aforementioned positive portion.

[0069] The wall friction coefficient Cf used to determine the spacing W1 between the pair of protrusions 32 and 33 can be arbitrarily changed as long as it is the wall friction coefficient near the peeling suppression portion 31 on the vehicle upper surface 201. For example, the wall friction coefficient of the portion of the vehicle upper surface 201 in front of the peeling suppression portion 31, specifically the portion behind the front end of the spoiler upper surface 211, may be used, or the wall friction coefficient of the portion in front of the front end of the spoiler upper surface 211 (the rear end portion of the roof 22) may be used. Alternatively, the wall friction coefficient of the portion of the spoiler upper surface 211 behind the peeling suppression portion 31, i.e., the portion located behind the peeling suppression portion 31, may also be used.

[0070] In addition to integrally molding the peeling suppression device 30 with the rear spoiler 21 so as to constitute a part of the upper wall of the rear spoiler 21, the rear spoiler 21 including the peeling suppression device 30 may also be formed by fixing a separately formed peeling suppression device 30 to the main body of the rear spoiler 21.

[0071] The delamination suppression device 30 is not limited to being installed on the upper surface 211 of the spoiler, but can be installed at any position on the outer surface of the vehicle 20, such as on the upper surface of the engine hood of the vehicle 20 or on the outer surface of the vehicle 20. When the delamination suppression device 30 is installed on the outer surface of the vehicle 20, the direction in which the pair of protrusions 32 and 33 are spaced apart should be the vertical direction Z. In this configuration, the vertical direction Z corresponds to the intersecting direction that crosses the longitudinal direction X when the vehicle 20 is moving.

[0072] The delamination suppression device 30 according to the above embodiment can be applied not only to mobile bodies that move on land (automobiles, automated guided vehicles, etc.), but also to mobile bodies that move in the air (aircraft, drones, etc.) and mobile bodies that move on or underwater (ships, submarines, etc.). In addition, the delamination suppression device 30 according to the above embodiment can also be applied to rotating mobile bodies (turbines, fans, etc.). In these configurations, the fluid flowing along the outer surface of the mobile body includes gases such as air, steam, and gaseous fuels, and liquids such as water. [Explanation of symbols]

[0073] 20... Vehicles 201... Top of the vehicle 21…Rear spoiler 211... Top of spoiler 22...Roof 221... Top of the roof 23...Boundary part 24...Reference plane 30... Peeling Inhibition Device 31... Peeling suppression section 32...First protruding section 33...Second protrusion 34...Concave groove part 341...bottom 35... protruding part 351... Upper surface of the convex part

Claims

1. A separation suppression device provided on the outer surface of a moving body, which suppresses the separation of fluid flow along the outer surface, The peeling suppression portion includes a pair of protruding portions arranged at intervals in an intersecting direction that intersects the front-rear direction when the moving body is in motion, and a recessed groove portion provided at a position sandwiched between the pair of protruding portions, The aforementioned protruding portion has a shape in which the outer surface protrudes, and becomes narrower towards the tip, forming a protrusion that extends in the front-rear direction. The aforementioned groove portion has a shape in which the outer surface is concave, and becomes narrower towards the bottom, forming a groove shape that extends in the front-rear direction. The coefficient of friction between the outer surface and the fluid flowing along that outer surface is such that the spacing between the pair of protrusions is determined according to the coefficient of friction between the outer surface and the vicinity of the peeling suppression portion. Peeling suppression device.

2. Multiple peel-inhibiting units are provided so as to be arranged in the intersecting direction. The structure in which the spacing is determined according to the coefficient of friction of the wall surface is applied separately to each of the plurality of peeling suppression parts. The peeling suppression device according to claim 1.

3. Assuming that the peeling suppression portion is not provided, and the surface constituting the outer surface is taken as the reference surface, The aforementioned interval is the interval on the reference surface. The peeling suppression device according to claim 1 or 2.

4. At the bottom of the groove, there is a protruding portion that extends in the front-rear direction, with the bottom surface of the groove protruding and becoming narrower towards the tip. The peeling suppression device according to claim 1 or 2.

5. The peel-suppressing portion is located in a part of the outer surface that has a positive pressure gradient, and is positioned in a part where the positive pressure gradient increases towards the rear in the front-rear direction. The peeling suppression device according to claim 1 or 2.

6. The aforementioned moving body is a vehicle having a rear spoiler. The fluid is air. The peeling suppression part is provided on the upper surface of the rear spoiler. The peeling suppression device according to claim 1 or 2.

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