Breakwater

Abstract

To realize high wave absorbing performance.SOLUTION: The floating breakwater 1 includes a first portion 12 extending along a first longitudinal direction, and a second portion 13 extending along a second longitudinal direction. The first longitudinal direction extends linearly from the D1 line J1 extending parallel to the wave traveling direction D1 toward the lower side of the wave as the first longitudinal direction extends away from the center line LA toward one side in the left-right direction perpendicular to the wave traveling direction LA in plan view. The second longitudinal direction extends linearly downward from the centerline J1 toward the other side in the left-right direction. The second part 13 is connected to an end portion on the other side in the left-right direction of the first part 12 on the center line J1. An angle θ formed by the first longitudinal direction and the second longitudinal direction is 90 ° or more and 150 ° or less. The first region 12 and the second region 13 are each provided with a water retarding portion 122,132 extending upward from the bottom through the water surface 91. In the floating wave-absorbing dike 1, high wave-absorbing performance can be realized by the structure.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a floating breakwater. [Background technology]

[0002] BACKGROUND ART Floating breakwaters, which are floating structures with wave-dissipating functions, have been used to achieve or promote calming of fishing grounds and ports.

[0003] For example, Patent Document 1 proposes a wave-dissipating float that has a shape in which two long ships are joined together in a planar V-shape, or in which a smaller ship is joined at the intersection of the two ships in a Y-shape. This wave-dissipating float is equipped with multiple pendulum-type wave energy absorbing devices on the entire side facing the open sea. This reduces wave force and also reduces the drifting force of the wave-dissipating float caused by waves. As a result, the tension acting on the mooring lines is reduced.

[0004] Patent Document 2 proposes a floating breakwater with a U-shaped or V-shaped planar shape. Patent Document 3 also proposes a floating breakwater in which multiple floating bodies with a U-shaped planar shape are arranged in a left-right direction perpendicular to the direction of wave travel. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 2838561 [Patent Document 2] Japanese Utility Model Application Publication No. 60-144610 [Patent Document 3] Japanese Patent Application Publication No. 10-227020 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the wave-dissipating float in Patent Document 1 has a complex shape made up of long ships, and multiple pendulum-type wave energy absorbing devices are installed on the entire side facing the open sea, which makes the structure complicated and increases manufacturing costs. On the other hand, reducing the number of wave energy absorbing devices in an attempt to reduce manufacturing costs reduces wave-dissipating performance.

[0007] Furthermore, in the floating breakwater of Patent Document 2, the angle at the apex (i.e., the center) of the V-shaped float is acute, so the width of the area below the waves of the float is narrow in the left-right direction, which is perpendicular to the direction of wave travel. This makes it difficult to achieve wave absorption over a wide area in the left-right direction. The same is true for each float of the floating breakwater of Patent Document 3.

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to achieve high wave-dissipating performance in a floating breakwater. [Means for solving the problem]

[0009] A first aspect of the present invention is a floating breakwater comprising: a first section extending along a first longitudinal direction that, in a plan view, extends from a centerline extending parallel to the direction of wave travel to one side in a left-right direction perpendicular to the direction of wave travel in a straight line toward the downstream side of the waves; and a second section connected to an end of the first section on the other side in the left-right direction on the centerline and extending along a second longitudinal direction that, in a straight line toward the downstream side of the waves, extends from the centerline to the other side in the left-right direction. The angle between the first longitudinal direction and the second longitudinal direction is 90° or more and 150° or less. The first section and the second section are provided with water retarding sections that extend upward from their bottoms through the water surface.

[0010] A second aspect of the present invention is a floating breakwater comprising: a first section extending along a first longitudinal direction that, in a plan view, extends from a centerline extending parallel to the direction of wave travel and that points linearly upward toward the upper reaches of the waves as it moves away from the centerline to one side in a left-right direction perpendicular to the direction of wave travel; and a second section connected to the end of the first section on the other side in the left-right direction on the centerline and that extends along a second longitudinal direction that points linearly upward toward the upper reaches of the waves as it moves away from the centerline to the other side in the left-right direction. The angle between the first longitudinal direction and the second longitudinal direction is 90° or more and 150° or less. The first section and the second section are provided with water retarding sections that extend upward from their bottoms through the water surface.

[0011] A third aspect of the present invention is a floating breakwater according to the second aspect, further comprising a wave-returning section that protrudes from the connection between the first section and the second section above the water surface toward the upper side of the waves and has a lower surface that faces the water surface in the vertical direction.

[0012] Aspect 4 of the present invention is a floating breakwater of any one of aspects 1 to 3, wherein the area of ​​the lower opening of the floodplain section in a plan view is smaller than the area of ​​a cross section perpendicular to the vertical direction at a position above the lower opening of the floodplain section.

[0013] A fifth aspect of the present invention is the floating breakwater of the fourth aspect, wherein the retarding section comprises a cylindrical side wall section that penetrates the water surface and surrounds a columnar internal space having the same cross section at each position in the vertical direction, and a frame-shaped flange section that protrudes from the lower end of the side wall section toward the internal space. The area inside the flange section is the lower opening.

[0014] A sixth aspect of the present invention is a floating breakwater according to any one of the first to third aspects (or any one of the first to fifth aspects), wherein the first portion comprises a pair of first main plates, each of which is a plate-like member extending along the first longitudinal direction and the vertical direction, and which constitute the upper and lower wave side surfaces of the floating breakwater, and a first partition plate, which is a plate-like member extending along the vertical direction, and which is disposed between the pair of first main plates to connect the pair of first main plates, thereby dividing the space between the pair of first main plates. The pair of first main plates and the first partition plate constitute side walls which surround the periphery of the retarding section.

[0015] A seventh aspect of the present invention is a floating breakwater according to any one of aspects 1 to 3 (or any one of aspects 1 to 6), further comprising an air-controlled wave-dissipating structure. The wave-dissipating structure comprises two connecting chambers spaced apart in the direction of travel and open downward. Each of the two connecting chambers comprises a cylindrical side wall surrounding a columnar internal space that penetrates the water surface, and a canopy that closes the upper opening of the side wall. The upper parts of the two connecting chambers are connected by a connecting pipe that allows air to move in the internal spaces of each of the two connecting chambers.

[0016] Aspect 8 of the present invention is a floating breakwater according to any one of Aspects 1 to 3 (or any one of Aspects 1 to 7), wherein the end face on one side in the left-right direction of the first section is perpendicular to the first longitudinal direction, and the end face on the other side in the left-right direction of the second section is perpendicular to the second longitudinal direction. [Effects of the Invention]

[0017] The present invention can achieve high wave-dissipating performance. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a perspective view of a floating breakwater according to a first embodiment. [Figure 2] This is a plan view of a floating breakwater. [Figure 3]A longitudinal cross-sectional view of a floating breakwater. [Figure 4] FIG. 10 is a perspective view of a floating breakwater according to a second embodiment. [Figure 5] This is a plan view of a floating breakwater. [Figure 6] A longitudinal cross-sectional view of a floating breakwater. [Figure 7] FIG. 10 is a perspective view of a floating breakwater according to a third embodiment. [Figure 8] This is a plan view of a floating breakwater. [Figure 9] A longitudinal cross-sectional view of a floating breakwater. [Figure 10] FIG. 10 is a plan view of a floating breakwater according to a fourth embodiment. [Figure 11] FIG. 10 is a perspective view of a floating breakwater according to a fifth embodiment. [Figure 12] FIG. 10 is a perspective view of a floating breakwater according to a sixth embodiment. [Figure 13] A longitudinal cross-sectional view of a floating breakwater. DETAILED DESCRIPTION OF THE INVENTION

[0019] Fig. 1 is a perspective view showing a floating breakwater 1 according to a first embodiment of the present invention. Fig. 2 is a plan view showing the floating breakwater 1. Fig. 3 is a longitudinal cross-sectional view of the floating breakwater 1 taken along the line III-III in Fig. 2. The floating breakwater 1 is a floating structure that is installed on the sea at fishing grounds, ports, etc., and that achieves or promotes calming of the sea area below the waves of the floating breakwater 1.

[0020] The floating breakwater 1 is a roughly box-shaped structure with multiple enclosed spaces 10 inside that serve as buoyancy chambers. The floating breakwater 1 has a roughly V-shaped shape when viewed from above. In the example shown in Figure 2, waves travel from the top to the bottom in the figure. In other words, the direction of wave travel is parallel to the vertical direction in Figure 2, and the top and bottom in Figure 2 are the wave upside and wave downside, respectively. In Figures 1 and 2, the wave travel direction is indicated by an arrow labeled D1.

[0021] The floating breakwater 1 has a generally V-shaped plan view that is convex toward the upstream side of the waves. The length of the floating breakwater 1 in the left-right direction in FIG. 2 (i.e., the direction perpendicular to the wave traveling direction D1) is, for example, 60 m to 120 m. In the following explanation, the central part of the floating breakwater 1 in the left-right direction in FIG. 2 (hereinafter simply referred to as the "left-right direction") that protrudes more than the surrounding parts in the wave traveling direction D1 is also referred to as the "breakwater body convex part 16." Furthermore, the central part of the floating breakwater 1 that is recessed more than the surrounding parts in the wave traveling direction D1 is also referred to as the "breakwater body concave part 17." In the example shown in FIG. 2, the breakwater body convex part 16 is located on the upstream side of the waves, and the breakwater body concave part 17 is located on the downstream side of the waves. The floating breakwater 1 is moored to the water bottom (e.g., the seabed) by mooring lines 51 extending from the breakwater body convex part 16 to the upstream side of the waves. The mooring method of the floating breakwater 1 is appropriately selected from various known mooring methods. The mooring of the floating breakwater 1 may be single-point mooring or multi-point mooring.

[0022] In the example shown in Figure 1, the shape of the floating breakwater 1 in plan view is substantially the same in any position in the vertical direction (i.e., in the direction of gravity). Therefore, the waterline shape of the floating breakwater 1 (i.e., the shape of the draft 93 shown by the two-dot chain line in Figure 1 in plan view) is also substantially V-shaped, similar to that shown in Figure 2.

[0023] In a plan view, the floating breakwater 1 has a shape that is approximately symmetrical with respect to a center line J1 that extends parallel to the wave traveling direction D1. The center line J1 is a straight line that passes through approximately the center of the side surface 18 of the floating breakwater 1 on the wave-upside and approximately the center of the side surface 19 on the wave-downside in the left-right direction in Figure 2. In the following explanation, the portion of the floating breakwater 1 that is located to the left of the center line J1 in Figure 2 will also be referred to as the "first portion 12." Furthermore, the portion of the floating breakwater 1 that is located to the right of the center line J1 in Figure 2 will also be referred to as the "second portion 13."

[0024] The first portion 12 and the second portion 13 are each a substantially rectangular parallelepiped portion. In FIG. 2, the right end of the first portion 12 is connected to the left end of the second portion 13 on the center line J1. As shown in FIG. 2, the first portion 12 extends in a substantially linear manner toward the underside of the waves as it moves away from the center line J1 to the left. The second portion 13 extends in a substantially linear manner toward the underside of the waves as it moves away from the center line J1 to the right. In the following description, the extension direction of the first portion 12 will also be referred to as the "first longitudinal direction," and the extension direction of the second portion 13 will also be referred to as the "second longitudinal direction."

[0025] In Fig. 2, the first longitudinal direction is a direction that extends in a substantially straight line toward the underside of the waves as it moves away from the center line J1 to the left (i.e., one side in the left-right direction). The second longitudinal direction is a direction that extends in a substantially straight line toward the underside of the waves as it moves away from the center line J1 to the right (i.e., the other side in the left-right direction). In the following description, in Fig. 2, the direction perpendicular to the first longitudinal direction is also referred to as the "first width direction," and the direction perpendicular to the second longitudinal direction is also referred to as the "second width direction."

[0026] In Figure 2, the center line of the first region 12 in the first width direction (hereinafter also referred to as the "first center line J2") is drawn by a dashed dotted line. The center line of the second region 13 in the second width direction (hereinafter also referred to as the "second center line J3") is also drawn by a dashed dotted line. The first region 12 extends in a substantially linear manner along the first center line J2, which extends in a linear manner parallel to the first longitudinal direction. The second region 13 extends in a substantially linear manner along the second center line J3, which extends in a linear manner parallel to the second longitudinal direction.

[0027] In Fig. 2, the angle θ formed by the first center line J2 and the second center line J3 (i.e., the angle θ formed by the first longitudinal direction and the second longitudinal direction) is 90° or more and 150° or less. The angle θ is preferably an obtuse angle greater than 90°. More preferably, the angle θ is 110° or more. Furthermore, the angle θ is preferably 130° or less.

[0028] In the example shown in Fig. 2, the left end face 121 of the first portion 12 is a substantially flat surface that is substantially perpendicular to the first longitudinal direction. In other words, the end face 121 of the first portion 12 is not parallel to the center line J1 in a plan view, but is inclined with respect to the center line J1. In addition, in the example shown in Fig. 2, the right end face 131 of the second portion 13 is a substantially flat surface that is substantially perpendicular to the second longitudinal direction. In other words, the end face 131 of the second portion 13 is not parallel to the center line J1 in a plan view, but is inclined with respect to the center line J1.

[0029] As shown in Figures 1 to 3, the first section 12 is provided with a water retention section 122 that extends upward from the bottom (i.e., the bottom surface 14 of the floating breakwater 1) through the water surface 91 (e.g., the sea surface). In the example shown in Figures 1 and 2, the first section 12 is provided with one water retention section 122. The water retention section 122 is provided, for example, in approximately the center of the first section 12 in the first longitudinal direction. Note that multiple water retention sections 122 may be provided in the first section 12. The multiple water retention sections 122 may be arranged, for example, in an approximately linear manner along the first longitudinal direction.

[0030] In the example shown in Figure 3, the flood retarding section 122 is a through-hole that extends approximately parallel in the vertical direction from the bottom surface 14 to the top surface 15 of the floating breakwater 1 and penetrates the first section 12. Inside the flood retarding section 122, there is water (e.g., seawater) that has entered through a lower opening 124 provided in the bottom surface 14 of the floating breakwater 1. The water surface 91 inside the flood retarding section 122 is located above the lower opening 124 of the flood retarding section 122 and below an upper opening 125 of the flood retarding section 122 provided on the top surface 15 of the floating breakwater 1. In other words, the internal space of the flood retarding section 122 is a space that extends vertically, penetrating the water surface 91.

[0031] In the example shown in FIG. 2, the shape of upper opening 125 of water retention section 122 in a plan view is approximately rectangular. Of the four sides of upper opening 125 in a plan view, one pair of sides is approximately parallel to the first longitudinal direction, and the other pair of sides is approximately perpendicular to the first longitudinal direction. The shape of water retention section 122 in a plan view is approximately the same as upper opening 125 at any position in the vertical direction (i.e., the direction of gravity) except for the lower end. In other words, the internal space of water retention section 122 is a space in the shape of an approximately rectangular column whose cross sections (i.e., cross sections perpendicular to the vertical direction) at each position in the vertical direction are approximately the same shape. The internal space of water retention section 122 extends approximately parallel to the vertical direction. Side wall portion 127 of water retention section 122 is a substantially rectangular tubular portion that surrounds the periphery of the internal space.

[0032] A flange portion 128 having a generally rectangular frame shape is provided at the lower end of the water retention portion 122, protruding generally horizontally from the lower end of the side wall portion 127 toward the internal space of the water retention portion 122. The flange portion 128 is a generally flat portion that is generally perpendicular to the up-down direction. The area inside the flange portion 128 is the lower opening 124 of the water retention portion 122. The shape of the lower opening 124 of the water retention portion 122 in a plan view is generally rectangular and smaller than the shape of the upper opening 125. In other words, the area of ​​the lower opening 124 of the water retention portion 122 in a plan view is different from and smaller than the area of ​​a cross section of the water retention portion 122 at a position above the lower opening 124. The upper end of the water retention portion 122 may be closed.

[0033] Similar to the first section 12, the second section 13 also has a water retention section 132. The water retention section 132 has substantially the same shape as the water retention section 122 of the first section 12, and is arranged so as to be substantially symmetrical with the water retention section 122 of the first section 12 about the center line J1 in a plan view.

[0034] Similar to the flood retarding section 122 of the first section 12, the flood retarding section 132 extends upward from the bottom of the second section 13 (i.e., the bottom surface 14 of the floating breakwater 1) through the water surface 91. In the example shown in Figures 1 and 2, there is one flood retarding section 132 provided in the second section 13. The flood retarding section 132 is provided, for example, in approximately the center of the second section 13 in the second longitudinal direction. Note that multiple flood retarding sections 132 may be provided in the second section 13. The multiple flood retarding sections 132 may be arranged, for example, in an approximately linear manner along the second longitudinal direction.

[0035] The flood retarding section 132 is a through-hole that extends substantially parallel in the vertical direction from the bottom surface 14 to the top surface 15 of the floating breakwater 1 and penetrates the second section 13. Inside the flood retarding section 132, there is water (e.g., seawater) that has entered through a lower opening 134 provided in the bottom surface 14 of the floating breakwater 1. The water surface 91 inside the flood retarding section 132 is located above the lower opening 134 of the flood retarding section 132 and below an upper opening 135 of the flood retarding section 132 provided on the top surface 15 of the floating breakwater 1. In other words, the internal space of the flood retarding section 132 is a space that extends vertically, penetrating the water surface 91.

[0036] In the example shown in FIG. 2, the shape of upper opening 135 of water retention section 132 in a plan view is approximately rectangular. Of the four sides of upper opening 135 in a plan view, one pair of sides is approximately parallel to the second longitudinal direction, and the other pair of sides is approximately perpendicular to the second longitudinal direction. The shape of water retention section 132 in a plan view is approximately the same as upper opening 135 at any position in the vertical direction (i.e., the direction of gravity) except for the lower end. In other words, the internal space of water retention section 132 is a substantially columnar space whose cross sections (i.e., cross sections perpendicular to the vertical direction) at each position in the vertical direction have approximately the same shape. The internal space of water retention section 132 extends approximately parallel to the vertical direction. Side wall portion 137 of water retention section 132 is a substantially rectangular tubular portion that surrounds the periphery of the internal space.

[0037] A flange portion 138 having a generally rectangular frame shape is provided at the lower end of the water retention portion 132, protruding generally horizontally from the lower end of the side wall portion 137 toward the internal space of the water retention portion 132. The flange portion 138 is a generally flat portion that is generally perpendicular to the up-down direction. The area inside the flange portion 138 is the lower opening 134 of the water retention portion 132. The shape of the lower opening 134 of the water retention portion 132 in a plan view is generally rectangular and smaller than the shape of the upper opening 135. In other words, the area of ​​the lower opening 134 of the water retention portion 132 in a plan view is different from and smaller than the area of ​​a cross section of the water retention portion 132 at a position above the lower opening 134. The upper end of the water retention portion 132 may be closed.

[0038] As described above, the floating breakwater 1 has a generally V-shape in plan view that is convex toward the upper side of the wave. Therefore, waves that enter the floating breakwater 1 from the upper side of the wave are dispersed in the left-right direction by the breakwater body convex portion 16 and the upper-side side surface 18, and flow outward in the left-right direction (i.e., in the direction away from the upper-side of the breakwater body convex portion 16) and toward the lower side of the wave. At positions on both sides of the breakwater body convex portion 16 in the left-right direction, waves flowing along the upper-side side surface 18 of the floating breakwater 1 collide with waves that directly enter these positions from the upper side of the wave, and are dissipated by canceling out due to the phase difference. Furthermore, in the floating breakwater 1, waves that enter the retarding sections 122, 132 from the lower openings 124, 134 and then exit the lower openings 124, 134 collide with waves passing below the lower openings 124, 134, and are dissipated by canceling out due to the phase difference. As a result, the floating breakwater 1 can achieve high wave-dissipating performance with a simple structure that requires relatively low manufacturing costs.

[0039] Furthermore, in a floating breakwater 1 that is approximately V-shaped in plan view, the apparent width B of the floating breakwater 1 in the wave travel direction D1 (i.e., the distance between the wave-upward end and wave-downward end of the floating breakwater 1 in the wave travel direction D1, hereinafter also referred to as "floating body width B") is large. As a result, the above-mentioned high wave-dissipating performance can be suitably demonstrated even for long waves in the travel direction D1 (i.e., waves with a relatively long period). The floating body width B of the floating breakwater 1 is, for example, 40m to 60m.

[0040] In addition, in the floating breakwater 1, for example, the breakwater body convex portion 16 may be made rounded in plan view (for example, R-shaped in plan view), so that the floating breakwater 1 has a substantially U-shaped shape in plan view. Even in this case, the floating body width B of the floating breakwater 1 is large, so the above-mentioned wave-dissipating performance can be suitably exhibited even for waves with a relatively long period. The same applies to the floating breakwater 1a (see Figure 4) described below.

[0041] Furthermore, in the floating breakwater 1, the angle θ between the first longitudinal direction and the second longitudinal direction is set to 150° or less, thereby ensuring a large floating body width B. As a result, wave-dissipating performance for long-period waves can be suitably demonstrated. Also, in the floating breakwater 1, the angle θ between the first longitudinal direction and the second longitudinal direction is set to 90° or more, thereby allowing the length of the floating breakwater 1 in the left-right direction to be increased. As a result, the length of the area calmed down the waves on the left-right side of the floating breakwater 1 can be increased.

[0042] From the viewpoint of improving the wave-dissipating performance against long-period waves, it is more preferable that the angle θ be 130° or less. Also, from the viewpoint of expanding the calming area, it is more preferable that the angle θ be greater than 90°, and even more preferably 110° or greater. The same applies to the floating breakwater 1a (see Figure 4) described below.

[0043] As described above, the floating breakwater 1 comprises a first section 12 extending along a first longitudinal direction and a second section 13 extending along a second longitudinal direction. The first longitudinal direction extends linearly from a center line J1 extending parallel to the wave propagation direction D1 in a plan view to one side in the left-right direction perpendicular to the wave propagation direction D1 (the left side in the example shown in FIG. 2 ) toward the wave bottom. The second longitudinal direction extends linearly to the other side in the left-right direction (the right side in the example shown in FIG. 2 ) from the center line J1 toward the wave bottom. The second section 13 is connected to the end of the first section 12 on the center line J1 on the other side in the left-right direction. The angle θ between the first longitudinal direction and the second longitudinal direction is 90° or more and 150° or less. The first section 12 and the second section 13 are provided with retarding sections 122, 132 extending upward from their bottoms through the water surface 91.

[0044] As described above, the floating breakwater 1 can achieve high wave-dissipating performance through the above structure. Furthermore, the floating breakwater 1 can effectively exert wave-dissipating performance against long-period waves, and the length of the area calmed down the waves of the floating breakwater 1 in the left-right direction can be increased.

[0045] As described above, it is preferable that the area of ​​lower opening 124 of flood retarding section 122 in a plan view is smaller than the area of ​​a cross section of flood retarding section 122 perpendicular to the up-down direction at a position above lower opening 124. This changes the speed of waves entering flood retarding section 122 from lower opening 124 (i.e., the speed of movement within flood retarding section 122), and creates a difference between the phase of the waves when they are discharged to the outside from lower opening 124 and the phase of the waves passing below lower opening 124. As a result, the wave-dissipating performance of flood retarding section 122 can be improved. In particular, the wave-dissipating performance for waves with a relatively long period can be suitably improved. The same applies to flood retarding section 132.

[0046] As described above, the flood retarding section 122 preferably includes a cylindrical side wall 127 and a frame-shaped flange 128. The side wall 127 penetrates the water surface 91 and surrounds a columnar internal space having the same cross-sectional shape at each vertical position. The flange 128 protrudes from the lower end of the side wall 127 toward the internal space. The area inside the flange 128 is the lower opening 124. This allows the area of ​​the lower opening 124 of the flood retarding section 122 in a plan view to be smaller than the cross-sectional area of ​​other parts of the flood retarding section 122, with a simple structure. Furthermore, the flange 128 dissipates the energy of waves passing through the lower opening 124, thereby further improving the wave-dissipating performance of the flood retarding section 122. The same applies to the flood retarding section 132.

[0047] As described above, it is preferable that the end face 121 on one side in the left-right direction of the first section 12 is perpendicular to the first longitudinal direction, and the end face 131 on the other side in the left-right direction of the second section 13 is perpendicular to the second longitudinal direction. This makes it possible to easily manufacture the first section 12 and the second section 13, and to simplify the structure of the floating breakwater 1.

[0048] Next, a floating breakwater 1a according to a second embodiment of the present invention will be described. Fig. 4 is a perspective view showing the floating breakwater 1a. Fig. 5 is a plan view showing the floating breakwater 1a. Fig. 6 is a longitudinal cross-sectional view of the floating breakwater 1a at the position VI-VI in Fig. 5.

[0049] The floating breakwater 1a has substantially the same shape as the floating breakwater 1 shown in Figures 1 to 3, except that a wave-reflecting portion 171a is provided in the breakwater body recess 17. The floating breakwater 1a is moored with the breakwater body recess 17 facing up the waves and the breakwater body protrusion 16 facing down the waves. In other words, the floating breakwater 1a is the floating breakwater 1 shown in Figure 2, rotated approximately 180° around a rotation axis extending in the vertical direction, and with a wave-reflecting portion 171a provided in the breakwater body recess 17. The other structure of the floating breakwater 1a is substantially the same as that of the floating breakwater 1 shown in Figures 1 to 3, and in the following explanation, the same reference numerals will be used to designate components of the floating breakwater 1a that correspond to those of the floating breakwater 1.

[0050] In the example shown in Figure 5, the first section 12 of the floating breakwater 1a is located to the right of a center line J1 that extends parallel to the wave travel direction D1, and the second section 13 is located to the left of the center line J1. The first section 12 extends in a substantially straight line toward the upper wave side as it moves away from the center line J1 to the right. The second section 13 extends in a substantially straight line toward the upper wave side as it moves away from the center line J1 to the left. As with the floating breakwater 1, a flood retarding section 122 is provided in the first section 12, and a flood retarding section 132 is provided in the second section 13.

[0051] In FIG. 5, the first longitudinal direction is a direction that extends in a substantially straight line toward the upper wave side as it moves away from the center line J1 to the right (i.e., one side in the left-right direction). The first center line J2 of the first section 12 extends substantially parallel to the first longitudinal direction. The second longitudinal direction is a direction that extends in a substantially straight line toward the upper wave side as it moves away from the center line J1 to the left (i.e., the other side in the left-right direction). The second center line J3 of the second section 13 extends substantially parallel to the second longitudinal direction. In FIG. 5, the angle θ formed by the first center line J2 and the second center line J3 (i.e., the angle θ formed between the first longitudinal direction and the second longitudinal direction) is 90° or more and 150° or less. As with the floating breakwater 1, the angle θ is preferably an obtuse angle greater than 90°. More preferably, the angle θ is 110° or more. Furthermore, the angle θ is preferably 130° or less.

[0052] The wave-reflecting portion 171a is a generally flat portion that is generally vertically perpendicular, and is provided at approximately the same height as the upper surface 15 of the floating breakwater 1a. The wave-reflecting portion 171a is disposed at a distance above the water surface 91. The lower surface 172a of the wave-reflecting portion 171a faces the water surface 91 in the vertical direction. The wave-reflecting portion 171a is provided above the space sandwiched between the first portion 12 and the second portion 13 near the breakwater body recess 17, and closes the upper end of the space. The wave-reflecting portion 171a protrudes upward from the connection between the first portion 12 and the second portion 13 in the breakwater body recess 17.

[0053] Because the floating breakwater 1a has a roughly V-shape in plan view that is convex toward the wave's downstream side, waves that enter the floating breakwater 1a from the upstream side flow inward in the left-right direction along the wave-upward side surface 19 of the floating breakwater 1a (i.e., in the left-right direction toward the breakwater body recess 17). At positions on both the left and right sides of the breakwater body recess 17, waves flowing along the wave-upward side surface 19 of the floating breakwater 1a collide with waves that directly enter these positions from the wave-upward side, and are dissipated by canceling out due to the phase difference. Also, in the floating breakwater 1a, as with the floating breakwater 1 described above, waves that enter the retarding sections 122, 132 from the lower openings 124, 134 and then exit from the lower openings 124, 134 collide with waves passing below the lower openings 124, 134, and are dissipated by canceling out due to the phase difference. As a result, the floating breakwater 1a can achieve high wave-dissipating performance with a simple structure that requires relatively low manufacturing costs.

[0054] Furthermore, in the case of the floating breakwater 1a, which is approximately V-shaped in plan view, the apparent width B of the floating breakwater 1a in the wave traveling direction D1 (i.e., floating body width B) is large, similar to the above-mentioned floating breakwater 1. As a result, the above-mentioned high wave-dissipating performance can be suitably exhibited even for long waves in the traveling direction D1 (i.e., waves with a relatively long period).

[0055] Furthermore, in the floating breakwater 1a, the angle θ between the first longitudinal direction and the second longitudinal direction is set to 150° or less, thereby ensuring a large floating body width B. As a result, wave-dissipating performance for long-period waves can be optimally demonstrated. Also, in the floating breakwater 1a, the angle θ between the first longitudinal direction and the second longitudinal direction is set to 90° or more, thereby allowing the length of the floating breakwater 1a in the left-right direction to be increased. As a result, the length of the area calmed down the waves on the left-right side of the floating breakwater 1a can be increased.

[0056] As described above, the floating breakwater 1a comprises a first section 12 extending along a first longitudinal direction and a second section 13 extending along a second longitudinal direction. The first longitudinal direction extends linearly from a center line J1 extending parallel to the wave propagation direction D1 in a plan view to one side in the left-right direction perpendicular to the wave propagation direction D1 (the right side in the example shown in FIG. 5). The second longitudinal direction extends linearly to the upper side of the waves as it moves away from the center line J1 to the other side in the left-right direction (the left side in the example shown in FIG. 5). The second section 13 is connected to the end of the first section 12 on the center line J1 on the other side in the left-right direction. The angle θ between the first longitudinal direction and the second longitudinal direction is 90° or more and 150° or less. The first section 12 and the second section 13 are provided with retarding sections 122, 132 extending upward from their bottoms through the water surface 91.

[0057] As described above, the floating breakwater 1a can achieve high wave-dissipating performance due to the above structure. Furthermore, the floating breakwater 1a can effectively exert wave-dissipating performance against long-period waves, and the length of the area calmed down the waves on the floating breakwater 1a in the lateral direction can be increased.

[0058] As described above, it is preferable that the floating breakwater 1a further includes a wave-reflecting portion 171a. The wave-reflecting portion 171a protrudes upward from the junction between the first portion 12 and the second portion 13 above the water surface 91. The wave-reflecting portion 171a has a lower surface 172a that faces the water surface 91 in the vertical direction. In the floating breakwater 1a, waves flowing along the wave-upward side surfaces 19 of the first portion 12 and the second portion 13 join together near the breakwater body recess 17 (i.e., near the junction between the first portion 12 and the second portion 13), causing the water surface 91 to rise near the breakwater body recess 17. Therefore, the wave-reflecting portion 171a knocks down and dissipates the waves that join together near the breakwater body recess 17, thereby improving the wave-dissipating performance of the floating breakwater 1a.

[0059] In the floating breakwater 1a, similarly to the floating breakwater 1, it is preferable that the area of ​​the lower opening 124 of the flood retarding section 122 in a plan view is smaller than the area of ​​a cross section perpendicular to the up-down direction at a position above the lower opening 124 of the flood retarding section 122. This changes the speed of waves entering the flood retarding section 122 from the lower opening 124 (i.e., the speed of movement within the flood retarding section 122), creating a difference between the phase of the wave when it is discharged to the outside from the lower opening 124 and the phase of the wave passing below the lower opening 124. As a result, the wave-dissipating performance of the flood retarding section 122 can be improved. In particular, the wave-dissipating performance for waves with a relatively long period can be suitably improved. The same applies to the flood retarding section 132.

[0060] In the floating breakwater 1a, similar to the floating breakwater 1, the retarding section 122 preferably comprises a cylindrical side wall 127 and a frame-shaped flange 128. The side wall 127 penetrates the water surface 91 and surrounds a columnar internal space having the same cross-sectional shape at each vertical position. The flange 128 protrudes from the lower end of the side wall 127 toward the internal space. The area inside the flange 128 is the lower opening 124. This allows the area of ​​the lower opening 124 of the retarding section 122 in a plan view to be smaller than the cross-sectional area of ​​other parts of the retarding section 122, with a simple structure. Furthermore, the flange 128 dissipates the energy of waves passing through the lower opening 124, thereby further improving the wave-dissipating performance of the retarding section 122. The same applies to the retarding section 132.

[0061] In the floating breakwater 1a, similar to the floating breakwater 1, it is preferable that the end face 121 on one side in the left-right direction of the first section 12 is perpendicular to the first longitudinal direction, and the end face 131 on the other side in the left-right direction of the second section 13 is perpendicular to the second longitudinal direction. This makes it possible to easily manufacture the first section 12 and the second section 13, and to simplify the structure of the floating breakwater 1a.

[0062] Next, a floating breakwater 1b according to a third embodiment of the present invention will be described. Fig. 7 is a perspective view showing the floating breakwater 1b. Fig. 8 is a plan view showing the floating breakwater 1b. Fig. 9 is a longitudinal cross-sectional view of the floating breakwater 1b at the position IX-IX in Fig. 8.

[0063] The shape of the floating breakwater 1b in plan view is generally V-shaped, convex toward the upper wave side, similar to the floating breakwater 1 described above. In plan view, the floating breakwater 1b has a shape that is generally symmetrical with respect to a center line J1 that extends parallel to the vertical direction in Figure 8 (i.e., the wave traveling direction D1). In the following description, the portion of the floating breakwater 1b located to the left of the center line J1 in Figure 8 will also be referred to as the "first portion 12b." Additionally, the portion of the floating breakwater 1b located to the right of the center line J1 in Figure 8 will also be referred to as the "second portion 13b." The right end of the first portion 12b is connected to the left end of the second portion 13b on the center line J1.

[0064] The floating breakwater 1b comprises a buoyancy section 21b, a first frame section 22b, and a second frame section 23b. The buoyancy section 21b is a substantially rectangular parallelepiped structure having an enclosed space 10b inside that serves as a buoyancy chamber. The buoyancy section 21b is positioned on the center line J1 and extends from the center line J1 to both sides in the left-right direction in FIG. 8 (hereinafter simply referred to as the "left-right direction").

[0065] The first frame portion 22b and the second frame portion 23b each have a frame structure formed by connecting a plurality of generally flat plate-shaped members extending in the vertical direction. The first frame portion 22b and the second frame portion 23b do not have an enclosed space that serves as a buoyancy chamber. In the example shown in FIG. 8, the first frame portion 22b is disposed to the left of the center line J1 and the buoyancy portion 21b, and the second frame portion 23b is disposed to the right of the center line J1 and the buoyancy portion 21b. The first frame portion 22b and the second frame portion 23b are connected to the buoyancy portion 21b.

[0066] In the floating breakwater 1b shown in Figure 8, the first portion 12b extending in a substantially straight line along the first longitudinal direction is formed by the first frame portion 22b and the portion of the buoyant portion 21b to the left of the center line J1. The second portion 13b extending in a substantially straight line along the second longitudinal direction is formed by the second frame portion 23b and the portion of the buoyant portion 21b to the right of the center line J1. The first longitudinal direction is a direction extending in a substantially straight line toward the wave bottom as the distance from the center line J1 increases to the left (i.e., one side in the left-right direction). The second longitudinal direction is a direction extending in a substantially straight line toward the wave bottom as the distance from the center line J1 increases to the right (i.e., the other side in the left-right direction).

[0067] The angle θ formed by the first center line J2, which is the center line of the first portion 12b, and the second center line J3, which is the center line of the second portion 13b (i.e., the angle θ formed by the first longitudinal direction and the second longitudinal direction), is 90° or more and 150° or less, similar to the floating breakwater 1 described above. The angle θ is preferably an obtuse angle greater than 90°. More preferably, the angle θ is 110° or more. Furthermore, the angle θ is preferably 130° or less.

[0068] In the example shown in Fig. 8, the left end face 121b of the first portion 12b is a substantially flat surface that is substantially perpendicular to the first longitudinal direction. In other words, the end face 121b of the first portion 12b is not parallel to the center line J1 in a plan view, but is inclined with respect to the center line J1. In addition, in the example shown in Fig. 8, the right end face 131b of the second portion 13b is a substantially flat surface that is substantially perpendicular to the second longitudinal direction. In other words, the end face 131b of the second portion 13b is not parallel to the center line J1 in a plan view, but is inclined with respect to the center line J1.

[0069] The first frame portion 22b of the first section 12b includes a pair of first main plates 221b, each of which is a substantially flat plate-like member extending in the first longitudinal direction and the up-down direction. The pair of first main plates 221b face each other while being spaced apart in the wave traveling direction D1. The wave-upward main surface of the first main plate 221b located on the wave-upward side of the pair of first main plates 221b forms the wave-upward side surface 18b of the floating breakwater 1b. The wave-downward main surface of the first main plate 221b located on the wave-downward side of the pair of first main plates 221b forms the wave-downward side surface 19b of the floating breakwater 1b.

[0070] The first frame portion 22b also includes a plurality of first partition plates 222b that are disposed between and connect the pair of first main plates 221b. Each of the first partition plates 222b is a substantially flat plate-shaped member that extends in the up-down direction and is substantially perpendicular to the first longitudinal direction. In the example shown in FIGS. 7 and 8, the first frame portion 22b includes two first partition plates 222b. In the first portion 12b, the space between the pair of first main plates 221b is partitioned (i.e., divided) by the plurality of first partition plates 222b.

[0071] 8, a substantially rectangular columnar space surrounded by a pair of first main plates 221b and two first partition plates 222b constitutes water retention section 122b, which extends upward from the bottom of first section 12b, penetrating water surface 91. The pair of first main plates 221b and the two first partition plates 222b constitute side wall section 127b that surrounds the periphery of water retention section 122b. In detail, the main surface on the lower wave side of first main plate 221b on the upper wave side and the main surface on the upper wave side of first main plate 221b on the lower wave side each constitute part of side wall section 127b of water retention section 122b.

[0072] 8, another water retention section 122b is provided inside the water retention section 122b in the left-right direction (i.e., on the side closer to the center line J1 in the left-right direction). The other water retention section 122b is a substantially columnar space surrounded by a pair of first main plates 221b, one first partition plate 222b, and the side surfaces of the buoyancy section 21b.

[0073] In first section 12b, the two water retention sections 122b are provided adjacent to each other in the first longitudinal direction. The number of water retention sections 122b provided in first section 12b may be one, or three or more. The number of first partition plates 222b may also be one, or three or more.

[0074] In the example shown in FIG. 8, the upper opening 125b of the water retention section 122b on the outer side in the left-right direction (i.e., the side farther from the center line J1 in the left-right direction) of the two water retention sections 122b has a generally rectangular shape in a plan view. Of the four sides of the upper opening 125b in a plan view, one pair of sides are generally parallel to the first longitudinal direction, and the other pair of sides are generally perpendicular to the first longitudinal direction. The shape of the water retention section 122b in a plan view is generally the same as that of the upper opening 125b at any position in the vertical direction (i.e., the direction of gravity) except for the lower end. That is, the internal space of the water retention section 122b is a generally rectangular columnar space whose cross sections (i.e., cross sections perpendicular to the vertical direction) have generally the same shape at each position in the vertical direction. The internal space of the water retention section 122b extends generally parallel to the vertical direction. The side wall portion 127b of the water retention section 122b is a generally rectangular cylindrical portion that surrounds the periphery of the internal space.

[0075] A flange portion 128b having a substantially rectangular frame shape is provided at the lower end of the water retention portion 122b, protruding substantially horizontally from the lower end of the side wall portion 127b toward the internal space of the water retention portion 122b. The flange portion 128b is a substantially flat portion that is substantially perpendicular to the up-down direction. The area inside the flange portion 128b is the lower opening 124b of the water retention portion 122b. The shape of the lower opening 124b of the water retention portion 122b in a plan view is a substantially rectangle that is smaller than the shape of the upper opening 125b. In other words, the area of ​​the lower opening 124b of the water retention portion 122b in a plan view is different from and smaller than the area of ​​a cross section of the water retention portion 122b at a position above the lower opening 124b. The upper end of the water retention portion 122b may be closed. In the example shown in FIG. 8, the inner water retention portion 122b in the left-right direction is also provided with a flange portion 128b in the same manner as the outer water retention portion 122b.

[0076] The second frame portion 23b of the second section 13b has a structure substantially similar to that of the first frame portion 22b. The second frame portion 23b includes a pair of second main plates 231b, each of which is a substantially flat plate-like member extending along the second longitudinal direction and the up-down direction. The pair of second main plates 231b face each other while being spaced apart from each other in the wave traveling direction D1. The wave-upward main surface of the second main plate 231b located on the wave-upward side of the pair of second main plates 231b forms the wave-upward side surface 18b of the floating breakwater 1b. The wave-downward main surface of the second main plate 231b located on the wave-downward side of the pair of second main plates 231b forms the wave-downward side surface 19b of the floating breakwater 1b.

[0077] The second frame portion 23b also includes a plurality of second partition plates 232b that are disposed between and connect the pair of second main plates 231b. Each second partition plate 232b is a substantially flat plate-shaped member that extends in the up-down direction and is substantially perpendicular to the second longitudinal direction. In the example shown in FIGS. 7 and 8, the second frame portion 23b includes two second partition plates 232b. In the second portion 13b, the space between the pair of second main plates 231b is partitioned (i.e., divided) by the plurality of second partition plates 232b.

[0078] 8, a substantially rectangular columnar space surrounded by a pair of second main plates 231b and two second partition plates 232b forms water retention section 132b, which extends upward from the bottom of second section 13b, penetrating water surface 91. The pair of second main plates 231b and the two second partition plates 232b form side wall section 137b that surrounds the periphery of water retention section 132b. In detail, the main surface on the lower wave side of second main plate 231b on the upper wave side and the main surface on the upper wave side of second main plate 231b on the lower wave side each form part of side wall section 137b of water retention section 132b.

[0079] 8, another water retention section 132b is provided inside the water retention section 132b in the left-right direction (i.e., on the side closer to the center line J1 in the left-right direction). The other water retention section 132b is a substantially columnar space surrounded by a pair of second main plates 231b, one second partition plate 232b, and the side surface of the buoyancy section 21b.

[0080] In second section 13b, the two water retention sections 132b are provided adjacent to each other in the second longitudinal direction. The number of water retention sections 132b provided in second section 13b may be one, or three or more. The number of second partition plates 232b may also be one, or three or more.

[0081] In the example shown in FIG. 8, the upper opening 135b of the water retention section 132b on the outer side in the left-right direction (i.e., the side farther from the center line J1 in the left-right direction) has a substantially rectangular shape in a plan view. In a plan view, one pair of four sides of the upper opening 135b are substantially parallel to the second longitudinal direction, and the other pair of sides are substantially perpendicular to the second longitudinal direction. The shape of the water retention section 132b in a plan view is substantially the same as that of the upper opening 135b at any position in the vertical direction (i.e., the direction of gravity) except for the lower end. That is, the internal space of the water retention section 132b is a substantially rectangular columnar space whose cross sections (i.e., cross sections perpendicular to the vertical direction) have substantially the same shape at each position in the vertical direction. The internal space of the water retention section 132b extends substantially parallel to the vertical direction. The side wall portion 137b of the water retention section 132b is a substantially rectangular cylindrical portion that surrounds the periphery of the internal space.

[0082] A flange portion 138b having a generally rectangular frame shape is provided at the lower end of the water retention portion 132b, protruding generally horizontally from the lower end of the side wall portion 137b toward the internal space of the water retention portion 132b. The flange portion 138b is a generally flat portion that is generally vertically perpendicular. The area inside the flange portion 138b is the lower opening 134b of the water retention portion 132b. The shape of the lower opening 134b of the water retention portion 132b in a plan view is generally rectangular and smaller than the shape of the upper opening 135b. In other words, the area of ​​the lower opening 134b of the water retention portion 132b in a plan view is different from and smaller than the area of ​​a cross section of the water retention portion 132b at a position above the lower opening 134b. The upper end of the water retention portion 132b may be closed. In the example shown in FIG. 8, the inner water retention portion 132b in the left-right direction is also provided with a flange portion 138b in the same manner as the outer water retention portion 132b.

[0083] As described above, floating breakwater 1b, like floating breakwater 1, has a generally V-shape in plan view that is convex toward the upper wave side, so waves that enter floating breakwater 1b from the upper wave side are dispersed in the left-right direction by breakwater body convex portion 16b and upper wave side surface 18b, and flow along said side surface 18b to the outside in the left-right direction (i.e., in the direction away from breakwater body convex portion 16b in the left-right direction) and toward the lower wave side. At positions on both sides of breakwater body convex portion 16b in the left-right direction, waves flowing along upper wave side surface 18b of floating breakwater 1b and waves that enter those positions directly from the upper wave side collide, and are dissipated by canceling each other out due to the phase difference. Furthermore, in the floating breakwater 1b, waves that enter the retarding sections 122b, 132b from the lower openings 124b, 134b and then exit from the lower openings 124b, 134b collide with waves passing below the lower openings 124b, 134b, and are dissipated by cancelling each other out due to the phase difference. As a result, the floating breakwater 1b can achieve high wave-dissipating performance with a simple structure that is relatively inexpensive to manufacture.

[0084] Furthermore, in the case of a floating breakwater 1b that is approximately V-shaped in plan view, the apparent width B of the floating breakwater 1b in the wave propagation direction D1 (i.e., floating body width B) is large. As a result, the above-mentioned high wave-dissipating performance can be suitably exhibited even for waves that are long in the propagation direction D1 (i.e., waves with a relatively long period). The floating body width B of the floating breakwater 1b is, for example, 40 to 60 meters.

[0085] In addition, the floating breakwater 1b may have a generally U-shaped plan view, for example, by making the breakwater body convex portion 16b rounded in plan view. Even in this case, the floating body width B of the floating breakwater 1b is large, so the above-mentioned wave-dissipating performance can be effectively exerted even for waves with a relatively long period. The same applies to the floating breakwater 1c (see Figure 10), which will be described later.

[0086] Furthermore, in the floating breakwater 1b, the angle θ between the first longitudinal direction and the second longitudinal direction is set to 150° or less, thereby ensuring a large floating body width B. As a result, wave-dissipating performance for long-period waves can be suitably demonstrated. Also, in the floating breakwater 1b, the angle θ between the first longitudinal direction and the second longitudinal direction is set to 90° or more, thereby allowing the length of the floating breakwater 1b in the left-right direction to be increased. As a result, the length of the area calmed down the waves on the left-right side of the floating breakwater 1b can be increased.

[0087] From the viewpoint of improving the wave-dissipating performance against long-period waves, it is more preferable that the angle θ be 130° or less. Also, from the viewpoint of expanding the calming area, it is more preferable that the angle θ be greater than 90°, and even more preferably 110° or greater. The same applies to the floating breakwater 1c (see Figure 10) described below.

[0088] As described above, the floating breakwater 1b comprises a first section 12b extending along a first longitudinal direction and a second section 13b extending along a second longitudinal direction. The first longitudinal direction extends linearly from a center line J1 extending parallel to the wave propagation direction D1 in a plan view to one side in the left-right direction perpendicular to the wave propagation direction D1 (the left side in the example shown in FIG. 8 ) toward the wave downstream side. The second longitudinal direction extends linearly from the center line J1 to the other side in the left-right direction (the right side in the example shown in FIG. 8 ). The second section 13b is connected to the end of the first section 12b on the center line J1 on the other side in the left-right direction. The angle θ between the first longitudinal direction and the second longitudinal direction is 90° or more and 150° or less. The first portion 12b and the second portion 13b are provided with water retention portions 122b, 132b that extend upward from the bottom through the water surface 91.

[0089] As mentioned above, the floating breakwater 1b can achieve high wave-dissipating performance due to the above structure.Furthermore, the floating breakwater 1b can effectively exert wave-dissipating performance against long-period waves, and the length of the area calmed down the waves on the floating breakwater 1b in the left-right direction can be increased.

[0090] As described above, the first section 12b preferably includes a pair of first main plates 221b and a first partition plate 222b. The pair of first main plates 221b are plate-like members extending along the first longitudinal direction and the vertical direction. The pair of first main plates 221b constitute the wave-upward side surface 18b and the wave-downward side surface 19b of the floating breakwater 1b. The first partition plate 222b is a plate-like member extending along the vertical direction. The first partition plate 222b is disposed between the pair of first main plates 221b and connects the pair of first main plates 221b, thereby dividing the space between the pair of first main plates 221b. The pair of first main plates 221b and the first partition plate 222b constitute the side wall portion 127b that surrounds the periphery of the retarding portion 122b. This allows the retarding portion 122b to be formed in the first section 12b with a simple structure. As a result, the floating breakwater 1b can be made lighter and less expensive.

[0091] The second section 13b preferably includes a pair of second main plates 231b and a second partition plate 232b. The pair of second main plates 231b are plate-like members extending along the second longitudinal direction and the vertical direction. The pair of second main plates 231b constitute the wave-upward side surface 18b and the wave-downward side surface 19b of the floating breakwater 1b. The second partition plate 232b is a plate-like member extending along the vertical direction. The second partition plate 232b is disposed between the pair of second main plates 231b and connects the pair of second main plates 231b, thereby dividing the space between the pair of second main plates 231b. The pair of second main plates 231b and the second partition plate 232b constitute a side wall portion 137b that surrounds the periphery of the retarding portion 132b. This allows the retarding portion 132b to be formed in the second section 13b with a simple structure. As a result, the floating breakwater 1b can be made lighter and less expensive.

[0092] In the floating breakwater 1b, similarly to the floating breakwater 1, the area of ​​the lower opening 124b of the flood retarding section 122b in a plan view is preferably smaller than the area of ​​a cross section of the flood retarding section 122b perpendicular to the up-down direction at a position above the lower opening 124b. This changes the speed of waves entering the flood retarding section 122b through the lower opening 124b (i.e., the speed of movement within the flood retarding section 122b), creating a difference between the phase of the waves when they are discharged to the outside through the lower opening 124b and the phase of the waves passing below the lower opening 124b. As a result, the wave-dissipating performance of the flood retarding section 122b can be improved. In particular, the wave-dissipating performance for waves with a relatively long period can be suitably improved. The same applies to the flood retarding section 132b.

[0093] In the floating breakwater 1b, similar to the floating breakwater 1, the retarding section 122b preferably comprises a cylindrical side wall 127b and a frame-shaped flange 128b. The side wall 127b penetrates the water surface 91 and surrounds a columnar internal space having the same cross-section at each vertical position. The flange 128b protrudes from the lower end of the side wall 127b toward the internal space. The area inside the flange 128b forms the lower opening 124b. This allows the area of ​​the lower opening 124b of the retarding section 122b in a plan view to be smaller than the cross-sectional area of ​​the rest of the retarding section 122b, even with a simple structure. Furthermore, the flange 128b dissipates the energy of waves passing through the lower opening 124b, further improving the wave-dissipating performance of the retarding section 122b. The same applies to the retarding section 132b.

[0094] In the floating breakwater 1b, it is preferable that the end face 121b on one side in the left-right direction of the first section 12b is perpendicular to the first longitudinal direction, and the end face 131b on the other side in the left-right direction of the second section 13b is perpendicular to the second longitudinal direction, similar to the floating breakwater 1. This makes it possible to easily manufacture the first section 12b and the second section 13b, and to simplify the structure of the floating breakwater 1b.

[0095] Next, we will explain a floating breakwater 1c according to a fourth embodiment of the present invention. Figure 10 is a plan view showing the floating breakwater 1c. The floating breakwater 1c has approximately the same shape as the floating breakwater 1b shown in Figures 7 to 9. The floating breakwater 1c is moored with the recessed portion 17b of the breakwater body facing up the waves and the protruding portion 16b of the breakwater body facing down the waves. In other words, the floating breakwater 1c is the floating breakwater 1b shown in Figure 8 rotated approximately 180° around a rotation axis extending in the vertical direction. The other structure of the floating breakwater 1c is approximately the same as that of the floating breakwater 1b shown in Figures 7 to 9, and in the following explanation, the same reference numerals will be used to designate the components of the floating breakwater 1c that correspond to those of the floating breakwater 1b.

[0096] In Figure 10, the first section 12b of the floating breakwater 1c is located to the right of the center line J1, and the second section 13b is located to the left of the center line J1. The first section 12b extends in a substantially straight line toward the upper wave side as it moves away from the center line J1 to the right. The second section 13b extends in a substantially straight line toward the upper wave side as it moves away from the center line J1 to the left. As with the floating breakwater 1b, the first section 12b is provided with a flood retarding section 122b, and the second section 13b is provided with a flood retarding section 132b.

[0097] In FIG. 10, the first longitudinal direction is a direction that extends in a substantially straight line toward the upper wave side as it moves away from the center line J1 to the right (i.e., one side in the left-right direction). The first center line J2 of the first portion 12b extends substantially parallel to the first longitudinal direction. The second longitudinal direction is a direction that extends in a substantially straight line toward the upper wave side as it moves away from the center line J1 to the left (i.e., the other side in the left-right direction). The second center line J3 of the second portion 13b extends substantially parallel to the second longitudinal direction. In FIG. 10, the angle θ formed by the first center line J2 and the second center line J3 (i.e., the angle θ formed between the first longitudinal direction and the second longitudinal direction) is 90° or more and 150° or less. As with the floating breakwater 1b, the angle θ is preferably an obtuse angle greater than 90°. More preferably, the angle θ is 110° or more. Furthermore, the angle θ is preferably 130° or less.

[0098] Because the floating breakwater 1c has a roughly V-shape in plan view, convex waves projecting downward from the wave bottom are incident on the floating breakwater 1c. Therefore, waves entering the floating breakwater 1c from the upper wave side flow inward in the left-right direction along the upper wave side 19b of the floating breakwater 1c (i.e., toward the breakwater body recess 17b in the left-right direction). At positions on both sides of the breakwater body recess 17b in the left-right direction, waves flowing along the upper wave side 19b of the floating breakwater 1c collide with waves directly entering the positions from the upper wave side, canceling out due to the phase difference, thereby dissipating the waves. Similarly to the floating breakwater 1b described above, waves entering the retarding sections 122b and 132b from the lower openings 124b and 134b and then exiting the lower openings 124b and 134b collide with waves passing below the lower openings 124b and 134b, thereby dissipating the waves due to the phase difference. As a result, the floating breakwater 1c can achieve high wave-dissipating performance with a simple structure that requires relatively low manufacturing costs.

[0099] Furthermore, in the case of the floating breakwater 1c, which is approximately V-shaped in plan view, the apparent width B of the floating breakwater 1c in the wave propagation direction D1 (i.e., floating body width B) is large, just like the floating breakwater 1b described above. As a result, the high wave-dissipating performance described above can be effectively exhibited even for long waves in the propagation direction D1 (i.e., waves with a relatively long period).

[0100] Furthermore, in the floating breakwater 1c, the angle θ between the first longitudinal direction and the second longitudinal direction is set to 150° or less, thereby ensuring a large floating body width B. As a result, the wave-dissipating performance for long-period waves can be suitably exhibited. Also, in the floating breakwater 1c, the angle θ between the first longitudinal direction and the second longitudinal direction is set to 90° or more, thereby allowing the length of the floating breakwater 1c in the left-right direction to be increased. As a result, the length of the area calmed down the waves on the left-right side of the floating breakwater 1c can be increased.

[0101] As described above, the floating breakwater 1c comprises a first section 12b extending along a first longitudinal direction and a second section 13b extending along a second longitudinal direction. The first longitudinal direction extends linearly from a center line J1 extending parallel to the wave propagation direction D1 in a plan view to one side in the left-right direction perpendicular to the wave propagation direction D1 (to the right in the example shown in FIG. 10). The second longitudinal direction extends linearly to the wave propagation direction as it moves away from the center line J1 to the other side in the left-right direction (to the left in the example shown in FIG. 10). The second section 13b is connected to the end of the first section 12b on the center line J1 on the other side in the left-right direction. The angle θ between the first longitudinal direction and the second longitudinal direction is 90° or more and 150° or less. The first portion 12b and the second portion 13b are provided with water retention portions 122b, 132b that extend upward from the bottom through the water surface 91.

[0102] As mentioned above, the floating breakwater 1c can achieve high wave-dissipating performance due to the above structure. Furthermore, the floating breakwater 1c can effectively exert wave-dissipating performance against long-period waves, and the length of the area calmed down the waves on the floating breakwater 1c in the left-right direction can be increased.

[0103] In the floating breakwater 1c, a wave returning section substantially similar to the wave returning section 171a of the floating breakwater 1a shown in Figures 4 to 6 may be provided near the breakwater body recess 17b. The wave returning section protrudes upward from the connection between the first section 12b and the second section 13b above the water surface 91, and has a lower surface that faces the water surface 91 in the vertical direction. This allows waves that join near the breakwater body recess 17b to be knocked down and dissipated by the wave returning section, substantially similar to the floating breakwater 1a, thereby improving the wave-dissipating performance of the floating breakwater 1c.

[0104] Next, a floating breakwater 1d according to a fifth embodiment of the present invention will be described. Figure 11 is a perspective view showing the floating breakwater 1d. The floating breakwater 1d has a similar structure to the floating breakwater 1b shown in Figures 7 to 9, except that buoyant sections 21d are provided at the outer left-right ends of the first section 12b and the second section 13b. In the following description, the same reference numerals will be used to designate the components of the floating breakwater 1d that correspond to those of the floating breakwater 1b.

[0105] Each buoyant section 21d, similar to the buoyant section 21b, is a substantially rectangular parallelepiped structure having an enclosed space therein that serves as a buoyancy chamber. In the first section 12b of the floating breakwater 1d, buoyant sections 21b, 21d are provided at both left-right ends, thereby reducing the force applied to the first frame section 22b. Similarly, in the second section 13b, buoyant sections 21b, 21d are provided at both left-right ends, thereby reducing the force applied to the second frame section 23b. This allows the weight of the first frame section 22b and the second frame section 23b of the floating breakwater 1d to be reduced.

[0106] Next, we will explain a floating breakwater 1e according to a sixth embodiment of the present invention. Fig. 12 is a perspective view showing the floating breakwater 1e. Fig. 13 is a longitudinal cross-sectional view of the floating breakwater 1e taken along the line XIII-XIII in Fig. 12. The floating breakwater 1e has a similar structure to the floating breakwater 1d shown in Fig. 11, except that an air-controlled wave-dissipating structure section 4e is provided in the buoyancy section 21b. In the following explanation, the same reference numerals will be used to designate the components of the floating breakwater 1e that correspond to those of the floating breakwater 1d.

[0107] The wave-dissipating structure 4e is a generally rectangular parallelepiped part with an open lower end, and is provided in the center in the left-right direction of the buoyancy section 21b. In the buoyancy section 21b, sealed spaces that serve as buoyancy chambers are provided on both left-right sides of the wave-dissipating structure 4e.

[0108] The wave-dissipating structure 4e includes a first chamber 41e, a second chamber 42e, and a third chamber 43e. The first chamber 41e, the second chamber 42e, and the third chamber 43e are each a substantially rectangular parallelepiped portion with an open bottom end. The first chamber 41e, the second chamber 42e, and the third chamber 43e are arranged along the wave traveling direction D1. In the example shown in FIG. 13, the first chamber 41e, the second chamber 42e, and the third chamber 43e are continuous (i.e., adjacent) in the wave traveling direction D1, but may also be spaced apart. The first chamber 41e, the second chamber 42e, and the third chamber 43e each penetrate the water surface 91. Water (e.g., seawater) enters the first chamber 41e, the second chamber 42e, and the third chamber 43e through openings provided at the bottom end of each chamber.

[0109] In the example shown in FIG. 13, the first chamber 41e, the second chamber 42e, and the third chamber 43e have substantially the same shape. Each of the first chamber 41e, the second chamber 42e, and the third chamber 43e includes a cylindrical sidewall 44e and a substantially flat canopy 45e. The sidewall 44e surrounds the periphery of a substantially rectangular columnar internal space that penetrates the water surface 91. The canopy 45e closes the upper opening of the sidewall 44e. A through-hole is provided in the center of the canopy 45e. The through-hole of the canopy 45e of the first chamber 41e and the through-hole of the canopy 45e of the third chamber 43e are connected by a connecting pipe 46e, through which air can move. In other words, the connecting pipe 46e connects the upper part of the first chamber 41e to the upper part of the third chamber 43e. Air in the internal space of first chamber 41e and air in the internal space of third chamber 43e moves between first chamber 41e and third chamber 43e via connecting pipe 46e. In the following description, first chamber 41e and third chamber 43e will also be referred to as "connecting chambers."

[0110] In the wave-dissipating structure 4e, when waves enter the first chamber 41e on the wave-upside and the water level in the first chamber 41e rises, the air in the first chamber 41e flows into the third chamber 43e via the connecting pipe 46e. In the third chamber 43e on the wave-downside, the air flowing in from the first chamber 41e pushes the water in the internal space out through the lower opening, lowering the water level. Below the third chamber 43e, the waves pushed out from the third chamber 43e collide with the waves that have passed below the first chamber 41e and the second chamber 42e and reached the bottom of the third chamber 43e, and the waves are dissipated by canceling each other out due to the phase difference.

[0111] As explained above, the floating breakwater 1e further comprises an air-controlled wave-dissipating structure 4e. The wave-dissipating structure 4e comprises two connecting chambers (i.e., a first chamber 41e and a third chamber 43e) that are spaced apart in the direction of travel D1 and open downward. Each of the two connecting chambers comprises a side wall 44e that surrounds the periphery of a columnar internal space that penetrates the water surface 91, and a canopy 45e that closes the upper opening of the side wall 44e. The upper parts of the two connecting chambers are connected by a connecting pipe 46e that allows air to move between the internal spaces of the two connecting sections. This improves the wave-dissipating performance of the floating breakwater 1e.

[0112] The wave dissipating structure 4e may be provided in the floating breakwater 1b shown in Fig. 7 or in the floating breakwater 1c shown in Fig. 10. Alternatively, the wave dissipating structure 4e may be provided in the floating breakwater 1 shown in Fig. 1 or in the floating breakwater 1a shown in Fig. 4. When the wave dissipating structure 4e is provided in the floating breakwater 1, 1a, the wave dissipating structure 4e is disposed, for example, between the retarding section 122 and the retarding section 132.

[0113] The floating breakwaters 1, 1a to 1e described above can be modified in various ways.

[0114] For example, in the floating breakwater 1, 1a, the end face 121 of the first section 12 does not necessarily have to be substantially perpendicular to the first longitudinal direction, but may be inclined relative to the first longitudinal direction. Similarly, the end face 131 of the second section 13 does not necessarily have to be substantially perpendicular to the second longitudinal direction, but may be inclined relative to the second longitudinal direction. For example, the end faces 121, 131 may be substantially parallel to the center line J1 in a plan view.

[0115] In the floating breakwaters 1b and 1c, the end face 121b of the first section 12b does not necessarily have to be substantially perpendicular to the first longitudinal direction, but may be inclined relative to the first longitudinal direction. Similarly, the end face 131b of the second section 13b does not necessarily have to be substantially perpendicular to the second longitudinal direction, but may be inclined relative to the second longitudinal direction. For example, the end faces 121b and 131b may be substantially parallel to the center line J1 in a plan view. Furthermore, in the floating breakwaters 1b and 1c, some or all of the end faces 121b and 131b may be omitted, and the outer left-right ends of the first frame section 22b and the second frame section 23b may be open.

[0116] The size of the floating breakwater 1 is not limited to the above example and may be modified in various ways. The same applies to the floating breakwaters 1a to 1e. In the floating breakwaters 1b and 1c, the ratio of the length of the buoyant section 21b to the overall length of the floating breakwaters 1b and 1c in the left-right direction and the wave traveling direction D1 is not limited to those shown in Figures 8 and 10 and may be modified in various ways. Furthermore, the buoyant section 21b does not necessarily have to be provided on the center line J1 and may be provided, for example, at the outer left-right ends of the first section 12b and the second section 13b.

[0117] In water retention section 122, the four sides of upper opening 125 in plan view do not have to be substantially parallel to the first longitudinal direction, and do not have to be substantially perpendicular to the first longitudinal direction. In water retention section 132, the four sides of upper opening 135 in plan view do not have to be substantially parallel to the second longitudinal direction, and do not have to be substantially perpendicular to the second longitudinal direction. Furthermore, the shape of water retention sections 122, 132 in plan view does not necessarily have to be substantially rectangular, and may be modified in various ways. For example, the shape of water retention sections 122, 132 in plan view may be substantially circular. The same applies to water retention sections 122b, 132b.

[0118] In water retention section 122, the area and shape of upper opening 125 may be the same as or different from the area and shape of lower opening 124 in a plan view. Furthermore, the area of ​​lower opening 124 of water retention section 122 in a plan view may be larger than or the same as the area of ​​a cross section perpendicular to the up-down direction at a position above lower opening 124 of water retention section 122. In water retention section 132, the area and shape of upper opening 135 may be the same as or different from the area and shape of lower opening 134 in a plan view. Furthermore, the area of ​​lower opening 134 of water retention section 132 in a plan view may be larger than or the same as the area of ​​a cross section perpendicular to the up-down direction at a position above lower opening 134 of water retention section 132. The same applies to water retention sections 122b, 132b.

[0119] In water retention section 122, for example, flange portion 128 may be omitted. Also, part or all of side wall portion 127 may be inclined relative to the vertical direction so that the cross-sectional area of ​​water retention section 122 gradually increases or decreases as it moves upward from lower opening 124. Similarly, in water retention section 132, flange portion 138 may be omitted. Also, part or all of side wall portion 137 may be inclined relative to the vertical direction so that the cross-sectional area of ​​water retention section 132 gradually increases or decreases as it moves upward from lower opening 134. The same applies to water retention sections 122b, 132b.

[0120] Water retention section 122 does not have to be provided in approximately the center of first section 12 in the first longitudinal direction, but may be located anywhere. Furthermore, water retention section 132 does not have to be provided in approximately the center of second section 13 in the second longitudinal direction, but may be located anywhere. The same applies to water retention sections 122b, 132b.

[0121] In the floating breakwaters 1 and 1a, the internal space of the water retention sections 122 and 132 does not necessarily have to extend substantially parallel to the vertical direction; for example, it may have a portion that bends substantially horizontally and extends substantially horizontally. Alternatively, the side walls 127 and 137 of the water retention sections 122 and 132 may be inclined surfaces that slope vertically. In this case, the cross section of the water retention sections 122 and 132 may, for example, increase or decrease in size as it extends upward from the lower openings 124 and 134. Similarly, in the floating breakwaters 1b and 1c, the internal space of the water retention sections 122b and 132b does not necessarily have to extend substantially parallel to the vertical direction; for example, it may have a portion that bends substantially horizontally and extends substantially horizontally. Alternatively, the side walls 127b and 137b of the water retention sections 122b and 132b may be inclined surfaces that slope vertically. In this case, the cross section of the water retention sections 122b, 132b may increase or decrease, for example, from the lower openings 124b, 134b upward.

[0122] In the above example, the wave-upward side surface 18 of the floating breakwater 1 and the wave-upward side surface 19 of the floating breakwater 1a are generally flat surfaces extending generally parallel in the vertical direction, but the shapes of the sides 18, 19 may be modified in various ways. For example, in the floating breakwater 1, the wave-upward side surface 18 may be a slope that slopes upward toward the wave-upward side, or a slope that slopes upward toward the wave-downward side. The same is true for the wave-upward side surface 19 of the floating breakwater 1a.

[0123] In the above example, the wave-upward side surface 18b of floating breakwater 1b and the wave-upward side surface 19b of floating breakwater 1c are substantially flat surfaces extending substantially parallel in the vertical direction, but the shapes of the sides 18b, 19b may be modified in various ways. For example, the wave-upward side surface 18b of floating breakwater 1b may be a slope that slopes upward toward the wave-upward side, or a slope that slopes upward toward the wave-downward side. The same is true for the wave-upward side surface 19b of floating breakwater 1c.

[0124] The floating breakwaters 1, 1a may have only one flood retarding section. In this case, the flood retarding section is provided, for example, straddling the first section 12 and the second section 13 of the floating breakwaters 1, 1a. Similarly, the floating breakwaters 1b, 1c may have only one flood retarding section. In this case, the flood retarding section is provided, for example, straddling the first section 12b and the second section 13b of the floating breakwaters 1b, 1c.

[0125] The configurations in the above-described embodiment and each modification may be combined as appropriate as long as they are not mutually contradictory. [Explanation of symbols]

[0126] 1,1a~1e Floating wave bank 4e Wave-dissipating structure 12,12b Part 1 13,13b 2nd part 18,18b,19,19b side 41e Room 1 43e Room 3 44e Side wall 45e Canopy 46e connecting pipe 91 Water surface 121,121b,131,131b End face 122, 122b, 132, 132b Flood control area 124,124b,134,134b Bottom opening 127,127b,137,137b Side wall part 128, 128b, 138, 138b flange 171a Wave return section 172a below 221b Motherboard 1 222b 1st cutting board D1 Direction J1 centerline θ angle

Claims

1. A floating breakwater, a first portion extending along a first longitudinal direction that extends linearly toward the underside of the waves as it moves away from a center line that extends parallel to the wave traveling direction in a plan view toward one side in a left-right direction perpendicular to the wave traveling direction; a second section that is connected to the other end of the first section in the left-right direction on the center line and extends along a second longitudinal direction that linearly extends toward a wave downstream side as it moves away from the center line toward the other side in the left-right direction; Equipped with an angle between the first longitudinal direction and the second longitudinal direction is greater than or equal to 90° and less than or equal to 150°; A floating breakwater in which a water retention section extending upward from the bottom through the water surface is provided in the first section and the second section.

2. A floating breakwater, a first portion extending along a first longitudinal direction that extends linearly toward the upper side of the waves as it moves away from a center line extending parallel to the wave traveling direction toward one side in a left-right direction perpendicular to the wave traveling direction in a plan view; a second section connected to the other end of the first section in the left-right direction on the center line and extending along a second longitudinal direction that linearly extends toward an up-wave side as it moves away from the center line toward the other side in the left-right direction; Equipped with an angle between the first longitudinal direction and the second longitudinal direction is greater than or equal to 90° and less than or equal to 150°; A floating breakwater in which a water retention section extending upward from the bottom through the water surface is provided in the first section and the second section.

3. The floating breakwater according to claim 2, A floating breakwater further comprising a wave-returning section that protrudes from the connection between the first section and the second section above the water surface toward the upper side of the waves and has a lower surface that faces the water surface in the vertical direction.

4. A floating breakwater according to any one of claims 1 to 3, A floating breakwater in which the area of ​​the lower opening of the floodplain section in a plan view is smaller than the area of ​​a cross section of the floodplain section perpendicular to the up-down direction at a position above the lower opening.

5. The floating breakwater according to claim 4, The water retention section is A cylindrical side wall portion that penetrates the water surface and surrounds a columnar internal space having the same cross section at each position in the vertical direction; a frame-shaped flange portion protruding from a lower end of the side wall portion toward the internal space; Equipped with The floating breakwater has an inner area of ​​the flange portion which is the lower opening.

6. A floating breakwater according to any one of claims 1 to 3, The first portion is a pair of first main plates, each of which is a plate-like member extending along the first longitudinal direction and the up-down direction and which constitutes the wave-upward and wave-downward side surfaces of the floating breakwater; a first partition plate that is a plate-like member extending along the up-down direction and is disposed between the pair of first main plates to connect the pair of first main plates, thereby partitioning a space between the pair of first main plates; Equipped with The pair of first main plates and the first partition plate form a floating breakwater that forms a side wall portion that surrounds the periphery of the water retention area.

7. A floating breakwater according to any one of claims 1 to 3, Further provided with an air-controlled wave-dissipating structure, The wave-dissipating structure includes two connecting chambers spaced apart from each other in the traveling direction and opening downward, The two connecting chambers each include: A cylindrical side wall portion surrounding a columnar internal space that penetrates the water surface; a canopy portion that closes an upper opening of the side wall portion; Equipped with The upper portions of the two connecting chambers are connected by a connecting pipe through which air in the internal spaces of the two connecting chambers can move.

8. A floating breakwater according to any one of claims 1 to 3, an end surface on the one side in the left-right direction of the first portion is perpendicular to the first longitudinal direction; A floating breakwater in which the end face on the other side in the left-right direction of the second section is perpendicular to the second longitudinal direction.

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