Vessel

Abstract

To provide a vessel capable of effectively reducing wind resistance against oblique head wind and generating thrust.SOLUTION: A vessel comprises a bow unit 2 positioned in the front of a hull 1, an upper deck 3 connected to the bow unit 2, and a pair of shipboard units 4, 4 positioned on both sides of the upper deck 3 and connected to the bow unit 2. The bow unit 2 includes a curved surface forming: a first contour line C1 including a clothoid curve with curvature radius increasing from a front side to a rear side of the hull 1 in a vertical cross section P1 of the hull 1; and a second contour line C2 including a clothoid curve with curvature radius increasing from the front side to the rear side of the hull 1 in a horizontal cross section P2 of the hull 1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a ship with low wind resistance, and more particularly to a ship that effectively reduces wind resistance against oblique headwinds and is capable of generating thrust. [Background technology]

[0002] For most commercial ships that travel on the water, there is a need to reduce resistance by adjusting the shape of the hull below the water line and to improve propulsion performance by tweaking the relationship between the hull, propeller, rudder, etc. In addition, efforts are made to reduce wave-making resistance and wave-breaking resistance caused by waves near the water line by adjusting the shape of the bow and stern.

[0003] On the other hand, there is also a demand for improvements in air resistance that occurs on the water surface, i.e., wind resistance, and various efforts are being made to address this. In particular, car carriers (PCCs) and passenger ships with large superstructures have a large surface area above the water surface that is susceptible to wind pressure, and as such, there are high hopes for reducing wind resistance, which will lead to energy savings.

[0004] In relation to this, a ship has been proposed that has low wind resistance, in which the shape of at least one of the above-water structures, the stern side of the superstructure installed on the upper deck, or the stern side of the hull above the water surface, is shaped so that in the shape of each cross section parallel to the water surface in at least a range of 0% to 50% of the vertical range of the above-water structure, it is outside an isosceles trapezoid whose bottom side is the rearmost part of the stern side of the maximum width B, the length B1 of the bottom side is 0.9 x B, the base angle θ1 is 40 deg to 80 deg, and the length B2 of the top side is 0.5 x B (see, for example, Patent Document 1).

[0005] Such ships with low wind resistance have a relatively large wind surface area above the waterline and are easily affected by wind pressure, such as car carriers, container ships, and passenger ships, so the aim is to reduce the effects of wind pressure and improve the ship's operational performance.Regarding headwinds, mainly from the front, a shape has been proposed that prevents the occurrence of outflow vortices such as stagnation vortices and Karman vortices in the dead water area behind the above-water structure.

[0006] Also, a hull has been proposed in which the shape of the hull above the water surface is a symmetrical NACA airfoil-type aerial foil, and the trailing edge on the stern side is cut off to form a cross section perpendicular to the fore-aft direction of the hull, so that aerodynamic lift in the direction of the ship's movement is generated by the relative wind and the hull functions as a sail (see, for example, Patent Document 2). The results of a wind tunnel test have been disclosed, which show that with this hull, a wind force component acting in the direction of the ship's movement was obtained in the wind sector of approximately 13 to 39 degrees.

[0007] As such, it is becoming increasingly important to reduce wind resistance not only from headwinds coming directly in the direction of the ship's travel, but also from diagonal headwinds, depending on the route the ship is traveling and the weather conditions at the time of voyage. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2011-57052 A [Patent Document 2] Special Publication No. 2014-501194 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present invention is to provide a ship which is capable of effectively reducing wind resistance against an oblique headwind and at the same time generating thrust. [Means for solving the problem]

[0010] In order to achieve the above object, a ship of the present invention has a bow located at the front of a hull, an upper deck connected to the bow, and a pair of side sections located on both sides of the upper deck and connected to the bow, The bow section is characterized by having a curved surface which, in a vertical cross-section of the hull, forms a first contour line including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull, and which, in a horizontal cross-section of the hull, forms a second contour line including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull. Effect of the Invention

[0011] As a result of extensive research into the shape of ships, the inventor discovered that by having a hull with curved surfaces that form a contour line that includes a clothoid curve in a specific cross section, the wind received while sailing can be smoothly guided along the hull and the wind flow can be stuck to the upper deck, reducing separation and the generation of vortices on the leeward side, while also generating negative pressure, which in turn generates thrust, leading to the invention.

[0012] That is, in the present invention, the bow section has a curved surface that forms a first contour line including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull in the vertical cross section of the hull, and a second contour line including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull in the horizontal cross section of the hull, thereby smoothly guiding the wind received during navigation along the hull and making the wind flow stick to the upper deck, thereby reducing separation and generation of vortexes on the leeward side. This makes it possible to effectively reduce wind pressure resistance, especially against oblique headwinds. In addition, when a bow section having a curved surface including the above-mentioned clothoid curve is provided, the wind on the upper deck can be accelerated. As a result, an effective resistance reduction effect is achieved when there is a headwind, and when there is an oblique headwind or a crosswind, the wind force can be converted to thrust to the maximum extent.

[0013] In the present invention, the curved surface of the bow preferably forms a third contour line including a clothoid curve whose radius of curvature increases from the outer side to the inner side in the width direction of the hull in the cross section of the hull. Also, the curved surface of the bow preferably forms a fourth contour line including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull in a cross section parallel to the center line of the hull and inclined to the vertical cross section. This allows for smooth passage of oblique headwinds and more effectively reduces wind resistance against oblique headwinds. Furthermore, when an oblique headwind or crosswind is received, the wind speed on the upper deck increases, eliminating stagnation on the leeward side and reducing resistance, and as a result, wind power can be converted to thrust to the maximum extent.

[0014] It is preferable that the gunwale section connecting the upper deck and each of the sides of the ship has a curved surface that forms a fifth contour line including a clothoid curve in which the radius of curvature increases from the outside to the inside in the width direction of the ship in the cross section of the hull. This allows the wind received during navigation to be smoothly guided along the hull, and the wind flow to be attached to the upper deck, reducing separation and generation of vortexes on the leeward side, and effectively reducing wind pressure resistance against crosswinds and oblique headwinds. In addition, when a gunwale section having the above-mentioned clothoid curve is provided together with a bow section having a curved surface including the above-mentioned clothoid curve, calculations based on computational fluid dynamics (CFD) show that the wind on the upper deck when an oblique headwind or crosswind is received can be accelerated by about 20% compared to the relative wind speed (the combined force of the ship's speed and natural wind) entering the ship. As a result, when an oblique headwind or crosswind is received, the wind force can be converted to thrust to the maximum extent.

[0015] It is preferable that the upper deck be constructed with a flat surface, which allows the wind received during sailing to be smoothly guided along the hull and keeps the wind flow attached to the upper deck, reducing separation and vortex generation on the leeward side, and effectively reducing wind resistance against crosswinds and diagonal headwinds.

[0016] It is preferable that the bow has a flat section at its front that is perpendicular to the centerline of the ship. This flat section acts as a wind guide when the ship receives an oblique headwind, and functions as an apparent camber for the wing, thereby contributing to an increase in thrust. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a front perspective view showing a vessel according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a side view of the vessel of FIG. 1. [Diagram 3] FIG. 2 is a perspective view showing contour lines of each part of the ship in FIG. 1. [Figure 4] FIG. 2 is a cross-sectional view showing a first contour line of the bow portion in a vertical cross section of the hull. [Diagram 5] FIG. 4 is a cross-sectional view showing a second contour line of the bow portion in a horizontal cross section of the hull. [Figure 6] FIG. 2 is a cross-sectional view showing a third contour line of the bow portion in a cross section of the hull. [Figure 7] FIG. 11 is a cross-sectional view showing a fourth contour line of the bow section in a cross section that is parallel to the centerline of the hull and inclined with respect to a vertical cross section. [Figure 8] A cross-sectional view showing the fifth contour line of the gunwale portion in a cross section of the hull. [Figure 9] FIG. 2 is a front perspective view showing wind flow relative to the ship of FIG. 1. [Figure 10] FIG. 11 is a front perspective view showing a vessel according to another embodiment of the present invention. [Figure 11] FIG. 11 is a side view of the vessel of FIG. [Figure 12] FIG. 11 is a perspective view showing contour lines of each part of the ship in FIG. [Figure 13] 3A and 3B show the thrust generated at the bow, where (a) is a plan view of a bow that does not have a flat portion, and (b) is a plan view of a bow that has a flat portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The configuration of the present invention will be described in detail below with reference to the accompanying drawings. Figures 1 to 8 show a ship according to an embodiment of the present invention. Note that the ship shown in Figures 1 to 8 is an example of a car carrier (car carrier), but the present invention is not particularly limited in its application as long as it satisfies certain requirements, and it can also be applied to passenger ships, ferries, etc.

[0019] 1 and 2, the ship of this embodiment is composed of a hull 1 with an overall length in the range of, for example, 40 m to 400 m. The hull 1 has a bow 2 located at the front, an upper deck 3 continuing from the bow 2, and a pair of side sections 4, 4 located on both sides of the upper deck 3 and continuing from the bow 2.

[0020] The hull 1 is provided with multiple decks (not shown) having a hierarchical structure inside, from the bow to the stern, in order to secure and transport automobiles. In addition, an opening for a rampway and its door (not shown) for loading and unloading automobiles are provided at the stern of the hull 1. A chimney 5 and the like are provided on the upper deck 3, but a tower such as a bridge or accommodation space is not provided. In this ship, the bridge (not shown) and accommodation space (not shown) are provided below the upper deck 3, and structures protruding from above the upper deck 3 are eliminated as much as possible. As shown in FIG. 2, a propeller 6 and a rudder 7 are provided at the lower part of the stern side of the hull 1. Here, one shaft and one rudder are provided, but this is not limited to this, and a multi-shaft ship such as two shafts and two rudders may be used.

[0021] In the ship configured as described above, the bow section 2 has a curved surface as shown in Fig. 3. The curved surface of the bow section 2 forms a first contour line C1 (see Fig. 4) including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 in a vertical cross section P1 of the hull 1, and forms a second contour line C2 (see Fig. 5) including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 in a horizontal cross section P2 of the hull 1. Furthermore, the curved surface of the bow section 2 forms a third contour line C3 (see Fig. 6) including a clothoid curve whose radius of curvature increases from the outside to the inside in the width direction of the hull 1 in a transverse cross section P3 of the hull 1. Moreover, the curved surface of the bow section 2 forms a fourth contour line C4 (see Fig. 7) including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 in a cross section P4 that is parallel to the center line CL of the hull 1 and inclined with respect to the vertical cross section P1. The center line CL of the hull 1 is an imaginary line extending along the longitudinal direction (horizontal direction) of the hull 1 at the center position of the hull 1 in the width direction.

[0022] A clothoid curve is a trajectory that is traced when the curvature is changed at a constant rate. The first contour line C1 of the bow section 2 in the vertical cross section P1 of the hull 1 includes a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 continuously or intermittently, and preferably includes the clothoid curve continuously. Therefore, the radii of curvature R11 to R13 of the first contour line C1 gradually increase toward the rear side of the hull 1, and the first contour line C1 is smoothly connected to the upper deck 3. Similarly, the second contour line C2 of the bow section 2 in the horizontal cross section P2 of the hull 1 includes a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 continuously or intermittently, and preferably includes the clothoid curve continuously. Therefore, the radii of curvature R21 to R23 of the second contour line C2 gradually increase toward the rear side of the hull 1, and the second contour line C2 is smoothly connected to the side section 4. The third contour line C3 of the bow 2 in the cross section P3 of the hull 1 includes a clothoid curve whose radius of curvature increases from the outside to the inside in the width direction of the hull 1 continuously or intermittently, and preferably includes the clothoid curve continuously. Therefore, the radii of curvature R31 to R33 of the third contour line C3 are gradually increased toward the inside in the width direction of the hull 1. The fourth contour line C4 of the bow 2 in the cross section P4, which is parallel to the center line CL of the hull 1 and inclined with respect to the vertical cross section P1, includes a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 continuously or intermittently, and preferably includes the clothoid curve continuously. Therefore, the radii of curvature R41 to R43 of the fourth contour line C4 are gradually increased toward the rear side of the hull 1, and the fourth contour line C4 is smoothly connected to the upper deck 3 or the side section 4.

[0023] In addition, in the ship configured as described above, the gunwale section 8 connecting the upper deck 3 and each of the ship's side sections 4 has a curved surface. The curved surface of the gunwale section 8 forms a fourth contour line C5 (see FIG. 8) including a clothoid curve whose radius of curvature increases from the outside to the inside in the width direction of the hull 1 in the cross section P5 of the hull 1. In other words, the fifth contour line C5 of the gunwale section 8 in the cross section P5 of the hull 1 includes a clothoid curve whose radius of curvature increases from the outside to the inside in the width direction of the hull 1 continuously or intermittently, and preferably includes the clothoid curve continuously. Therefore, the radii of curvature R51 to R53 of the fifth contour line C5 gradually increase toward the inside in the width direction of the hull 1, and the fifth contour line C5 is smoothly connected to the upper deck 3.

[0024] According to the above-mentioned ship, the bow section 2 has a curved surface that forms a first contour line C1 including a clothoid curve whose radius of curvature increases from the front side to the rear side of the ship 1 in the vertical cross section P1 of the ship 1, and forms a second contour line C2 including a clothoid curve whose radius of curvature increases from the front side to the rear side of the ship 1 in the horizontal cross section P2 of the ship 1. Therefore, as shown in FIG. 9, for example, when an oblique headwind is received during navigation, the wind can be smoothly guided along the ship 1, and the wind flow can be made to stick to the upper deck 3, thereby reducing separation and generation of vortexes on the leeward side. This makes it possible to effectively reduce wind pressure resistance against an oblique headwind. In addition, when an oblique headwind is received during navigation, the wind pressure can be converted to thrust to the maximum extent. As a result, fuel efficiency can be improved and energy saving can be achieved in the operation of the ship.

[0025] In the above-mentioned ship, it is preferable that the curved surface of the bow section 2 forms a third contour line C3 including a clothoid curve whose radius of curvature increases from the outer side to the inner side in the width direction of the hull 1 in the cross section P3 of the hull 1. In this case, it is possible to allow a diagonal headwind to pass smoothly and to more effectively reduce wind pressure resistance against the diagonal headwind. It is also preferable that the curved surface of the bow section 2 forms a fourth contour line C4 including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 in a cross section P4 that is parallel to the center line CL of the hull 1 and inclined with respect to the vertical cross section P1. In this case, it is possible to allow a diagonal headwind to pass smoothly and to more effectively reduce wind pressure resistance against the diagonal headwind.

[0026] Furthermore, in the above-mentioned ship, it is desirable that the gunwale sections 8 connecting the upper deck 3 and each of the ship's side sections 4 have a curved surface that forms a fifth contour line C5 including a clothoid curve whose radius of curvature increases from the outer side to the inner side in the width direction of the hull 1 in the cross section P5 of the hull 1. In this case, the wind received during navigation can be smoothly guided along the hull 1, and the wind flow can be made to stick to the upper deck 3, reducing separation and vortex generation on the leeward side, effectively reducing wind pressure resistance against crosswinds and diagonal headwinds.

[0027] Moreover, in the above-mentioned ship, it is preferable that the upper deck 3 is configured as a flat surface extending in the horizontal direction. In this case, the wind received during navigation can be smoothly guided along the hull 1, and the wind flow can be made to stick to the upper deck 3, reducing separation and vortex generation on the leeward side, thereby effectively reducing wind pressure resistance against crosswinds and diagonal headwinds. It is preferable that the upper deck 3 is configured as flat as possible, but the provision of a minimum number of protrusions such as a chimney 5 is permitted. For example, it is sufficient that the ratio of the area of ​​the flat parts to the total area of ​​the upper deck 3 (excluding the curved parts and corner cut parts of the bow section 2 and gunwale section 8) is 90% or more.

[0028] 10 to 12 show a ship according to another embodiment of the present invention. In Figs. 10 to 12, the same parts as those in Figs. 1 to 8 are denoted by the same reference numerals, and detailed description of those parts is omitted. In the ship of this embodiment, the bow section 2 satisfies the condition that the bow section 2 has a curved surface that forms a first contour line C1 including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 in a vertical cross section P1 of the hull 1, a second contour line C2 including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 in a horizontal cross section P2 of the hull 1, a third contour line C3 including a clothoid curve whose radius of curvature increases from the outside to the inside in the width direction of the hull 1 in a transverse cross section P3 of the hull 1, and a fourth contour line C4 including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull 1 in a cross section P4 that is parallel to the center line CL of the hull 1 and inclined to the vertical cross section P1. However, the shape of the bow section 2 is slightly different from that of the above-mentioned embodiment.

[0029] In particular, the bow 2 is provided with a flat portion 9 at its front end, which is a plane perpendicular to the center line CL of the ship 1. When such a flat portion 9 is provided, the flat portion 9 acts as a wind guide and functions as an apparent camber of the wing when the ship 1 receives an oblique headwind, so that the thrust can be increased. That is, when the bow 2 has a flat portion 9 as shown in FIG. 13(b), the flat portion 9 functions as an apparent camber of the wing when guiding the wind downwind, so that a larger thrust F can be obtained, compared to when the bow 2 does not have a flat portion 9 as shown in FIG. 13(a). This effect is produced for winds flowing in from both the left and right sides. The width of the flat portion 9 is preferably 1 / 3 or less of the overall width of the hull 1.

[0030] The area of ​​the flat section 9 can be adjusted according to the normal operating speed of the ship. For example, in the case of a ship traveling at a high speed and thus experiencing crosswinds less frequently, the flat section 9 is made small or a structure without a flat section 9 (see FIG. 1) is used. On the other hand, in the case of a ship traveling at a low speed and thus experiencing crosswinds more frequently, a structure with a large flat section 9 is used (see FIG. 10). [Explanation of symbols]

[0031] 1. Hull 2 Fore part 3 Upper Deck 4 Ship side 5. Chimney 6 Propellers 7. Rudder 8 Gunwale 9 Flat section C1 First contour line C2 Second contour line C3 Third contour line C4 Fourth contour line C5 Fifth contour line

Claims

1. A ship having a bow located at the front of the hull, an upper deck connected to the bow, and a pair of side sections located on both sides of the upper deck and connected to the bow, The bow section has a curved surface that, in a vertical cross section of the hull, forms a first contour line including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull, and that, in a horizontal cross section of the hull, forms a second contour line including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull.

2. 2. The ship according to claim 1, wherein the curved surface of the bow defines a third contour line in a cross section of the hull, the third contour line including a clothoid curve whose radius of curvature increases from the outer side to the inner side in the width direction of the hull.

3. 2. The ship according to claim 1, wherein the curved surface of the bow defines a fourth contour line including a clothoid curve whose radius of curvature increases from the front side to the rear side of the hull in a cross section that is parallel to the center line of the hull and inclined with respect to the vertical cross section.

4. The ship according to claim 1, characterized in that the gunwale portion connecting the upper deck and each of the side portions has a curved surface that forms a fifth contour line in a cross section of the hull, the fifth contour line including a clothoid curve whose radius of curvature increases from the outer side to the inner side in the width direction of the hull.

5. 5. The ship according to claim 1, wherein the upper deck is constructed of a flat surface.

6. 5. The ship according to claim 1, wherein the bow has at its foremost part a flat portion consisting of a plane perpendicular to the center line of the ship.

Images