JP5638215B2 - Ship with low wind pressure resistance and its design method - Google Patents

Description

The present invention relates to small ships, wind resistance, and more particularly relates to a marine vessel and the design method thereof to reduce the wind resistance by devising the stern side of the shape of the upper structures such as bridge or living quarters.

  Most of the merchant vessels that run on the water are called the displacement type, and during navigation, they have a part below the surface of the water and a part above the surface of the water. While receiving resistance and resistance from air (wind) on the surface of the water, the ship is sailing by thrust generated by a propeller such as a propeller.

  Under the surface of the ship, drag reduction and improvement of propulsion performance due to the relationship between the hull, propeller, and rudder are being promoted under the shape of the hull. Regarding resistance reduction, resistance reduction has been achieved by devising the bow shape and stern shape. A great deal of effort has been spent on these and efforts are continuing.

  On the other hand, with respect to resistance due to air on the surface of the water, conventionally, the amount of resistance under the surface of the water and in the vicinity of the surface of the water is large, and there has been an improvement effect by devising the shape of the hull. However, as the amount of resistance under and near the water surface decreases, the demand for improvement in air resistance, that is, wind pressure resistance, has increased.

  In particular, car carriers with large psoriasis and a large wind pressure area, container ships that increase the wind pressure area due to loading of cargo, and passenger ships with large upper structures are susceptible to wind pressure due to the large wind pressure area on the water surface. . Therefore, direct resistance increase due to wind pressure resistance, underwater resistance increases due to tilting by the hull attitude change due to wind pressure, and indirect resistance increase due to rudder to maintain the course, etc. There were problems with operational performance, such as a decline.

  In this connection, a semi-cylindrical body is vertically attached to the front wall of the upper structure located on the upper deck of the ship to form a hollow structure, and an air inlet having a trumpet-shaped enlarged portion at the lower end of the hollow structure The air discharge port is provided at the upper end, the air hitting the lower part of the front wall of the upper structure is sucked in by the air suction port, sucked up by the chimney effect and released from the air discharge port, the pressure on the front surface of the front wall is reduced. There has been proposed a ship wind pressure resistance reduction device that reduces the wind pressure resistance of the front surface of the upper structure.

  In addition, in an automobile-only ship with a plurality of vehicle-mounted decks, a bow-side mooring window can be closed on the outer plate surrounding the bow-side mooring deck where the mooring machine is placed to suppress disturbances in the airflow near the bow. The stern side mooring deck uses a retractable flap, notch, etc. as an air inflow promoting means, making the air flow smooth and suppressing the increase in wind pressure resistance due to the turbulence of the airflow. A vehicle-only ship has been proposed that reduces the wind pressure resistance of the entire hull by accelerating the inflow of air into the stern and sending the air to a negative pressure region near the stern for pressure recovery (for example, Patent Document 2). reference.).

  Also, the main hull is separated from the bow at the upper part of the hull side, is located at the bow side of the upper structure, is continuous with the upper end of the outer wall of the ship, and rises from the position away from the bow, as it goes toward the stern. The structure of the main hull is changed by providing a windbreak fence that gradually increases in height, and making the surface facing the outside of the main hull of this windbreak fence an inclined surface with the upper end positioned on the upper structure side of the lower end There has been proposed a ship that reduces air resistance without doing so (see, for example, Patent Document 3).

  In these ships, the shape of the superstructure remains unchanged, and the wind pressure resistance is reduced by changing the flow of the surrounding air. On the other hand, it is considered to reduce the wind pressure resistance by changing a part of the hull shape.

  As one of such ships, a notch step portion is provided at both corners connecting the upper deck and both sides of the hull over the entire length from the bow to the stern, or from the bow to almost the center of the hull. There has been proposed a ship in which an inclined surface that is upwardly inclined with respect to a horizontal plane is formed on the bow from the upper end of the front edge of the bow toward the upper deck (see, for example, Patent Document 4).

  In addition, at each corner formed by the upper deck of the hull and both sides, a notch step formed along the direction from the bow to the stern, a ventilation unit provided on at least one notch step, and a ventilation There has been proposed a marine vessel that includes a housing that covers a unit and has a housing formed on a first inclined surface with a corner portion located on the side of the heel side formed by an upper surface and a side surface (see, for example, Patent Document 5).

  In these vessels, this notched step suppresses separation and vortex generation at the corners connecting the upper deck and the heel side against oblique winds, reducing resistance, lateral force, and yaw moment due to wind pressure. This has been confirmed by wind tunnel experiment results and CFD (Computational Fluid Dynamics) analysis results. However, it is considered that there is room for improvement with respect to the square shape of the superstructure provided on the upper deck and the square shape of the stern.

  As described above, in the prior art, for the upper structure provided above the upper deck such as a bridge or a residential area, because it dislikes the reduction of the volume, without considering a large shape change, the conventional box type The shape was close to the combination of the above, and it was just a contrivance such as attaching an additional structure that changes the flow of wind around the superstructure.

  However, while taking into account the miniaturization of navigation equipment and the steering mechanism, the improvement of fuel efficiency and the increase / decrease of the volume due to resistance reduction, the rear part of the hull that receives the wind above the waterline and the shape behind the superstructure The actual situation is that no consideration has been given to an overall improvement in which the shape of the above is greatly changed in order to reduce the wind resistance.

JP-A-6-183392 JP 2005-82030 A JP 2005-132314 A Japanese Patent Laid-Open No. 2003-291883 JP 2006-36118 A

An object of the present invention is to improve the ship's operational performance by reducing the influence of wind pressure on a dedicated car, container ship, passenger ship, etc., which has a relatively large wind pressure area on the water surface and is susceptible to wind pressure. An object of the present invention is to provide a ship with low wind pressure resistance and a design method thereof .

The ship with low wind pressure resistance for achieving the above object is a ship having a navigation speed and a fluid number related to the navigation speed of the ship of 0.13 to 0.30, and an upper structure provided on the upper deck. The shape of the structure on the water surface of the stern side of the hull or the shape of the stern side of the hull on the surface of the water is set to the stern side when moving forward in the preset wind speed at the nautical speed. A swirl with a diameter ranging from three times the maximum width of the structure on the water surface to one tenth of the maximum width is generated at a position behind the vertical line by a length of 0.2 x vertical line. In the shape of the water surface structure ,
In the case of an upper structure having a bridge, when the maximum width excluding the dodger and the support structure of the dodger is defined as B, the shape of the stern side of the structure on the water surface is set in the vertical direction of the structure on the water surface. In the shape of each cross section parallel to the water surface in the range of at least 0% to 50% of the range, the stern side rearmost portion of the maximum width B is the lower side, and the length B1 of the lower side is 0.9 × B, The bottom angle θ1 is 40 deg to 80 deg, the upper side length B2 is 0.5 × B, the outer side of the isosceles trapezoid, and the stern side rearmost part of the maximum width B is the bottom side, The length B3 is 1.2 × B and the base angle θ2 is 40 deg to 80 deg . The preset wind speed is usually a design wind speed set from the wind speed of the assumed sea area where the target ship navigates, and is a wind speed determined from the design specifications. The voyage speed is also determined from the design specifications.
Further, a ship design method with a low wind pressure resistance to achieve the above object is a ship having a navigation speed and a fluid number related to the navigation speed of the ship of 0.13 to 0.30. The shape of the structure on the water surface, which is the shape of the stern side of the stern, on the stern side when moving forward in the preset wind speed at the nautical speed, the position behind the stern vertical line 0.2 × the length between the vertical lines In the shape of the above water surface structure, no eddy current is generated having a diameter ranging from three times the maximum width of the above water surface structure to one tenth of this maximum width. In the case of an upper structure having a structure where the maximum width excluding the dodger and the support structure of the dodger is B, the shape of the stern side of the structure on the water surface is the vertical range of the structure on the water surface. On the water surface in the range of at least 0% to 50% In each cross-sectional shape, the rearmost part of the stern side of the maximum width B is the lower side, the length B1 of the lower side is 0.9 × B, the base angle θ1 is 40 deg to 80 deg, and the length B2 of the upper side is 0 .5 × B outside the isosceles trapezoid, and the stern side rearmost portion of the maximum width B is the base, the base length B3 is 1.2 × B, and the base angle θ2 is 40 degrees. It is a method characterized in that it is formed so as to enter a region inside an isosceles triangle of ˜80 deg .

  Note that this vortex is an outflow vortex such as a stagnant vortex or Karman vortex generated in the dead water region, and is a vortex of an equivalent size when compared with the size of the structure on the water surface. It is not a problem for small vortices that are small compared to the magnitude of the wind pressure resistance that does not significantly affect the wind pressure resistance that is a problem of the present invention. For example, the stern perpendicular A. P. 10 minutes of the maximum width of the structure on the surface of the water (excluding the dodger and the support structure of the dodger in the case of the upper structure having a bridge) at a position behind 0.2 × Lpp (length between vertical lines) A vortex of 1 or less is not a problem. In other words, to be strong, the “eddy current” referred to here is the stern perpendicular line A. P. In the position behind 0.2 × Lpp (length between perpendiculars), the size of the maximum width B is three times the maximum width B of the structure on the water surface (if an upper limit is shown) and is one tenth of the maximum width B. It means a vortex with a diameter of up to

The fluid number Fn is Fn = V / (Lpp × g) ^1/2 , where V is the ship speed, Lpp is the length between the perpendiculars, and g is the gravitational acceleration. Here, the reason why the Froude number Fn of the ship targeted by the present invention is set to 0.13 to 0.30 is that the Froude number Fn is larger than 0.30. This is to distinguish the stealth technique from the stealth cover, because the entire hull may be covered and covered.

  According to said structure, the fairing part which forms a smooth flow is provided in the stern side of the upper structure, such as a bridge and a residential area, and the hull on the water surface. The wind pressure resistance due to the wind from the front is the largest when the aircraft moves forward in the preset wind speed at the speed of the voyage. At this time, there is a vortex (stagnation vortex and Karman vortex in the dead water area) on the stern side. If there is no flow vortex, the wind pressure resistance will be low, so the entire stern on the water surface of the conventional transom shape, etc. The wind pressure resistance can be reduced as compared with the shape.

  Whether or not a vortex is generated on the stern side can be easily verified by wind tunnel model experiments and numerical fluid simulations, and the specific shape is also the result of these wind tunnel model experiments and numerical fluid simulations. It can be easily determined from the known shape.

  A dodger is a structure that is formed to extend from the steering wheel of the bridge in both the left and right directions so that personnel can move to the side of the shore to monitor the shore when maneuvering at the time of berthing or leaving the berth. .

  Also, if it is in this range in plan view, it is possible to avoid the occurrence of large vortices on the stern side with respect to the wind from the front, so it is possible to save time and effort to verify by wind tunnel model experiments and numerical fluid simulation. it can.

  And by adopting such a shape, when applied to the stern side of the hull on the surface of the water, the stern part is extended, thereby increasing the length of the water line, and the separation flow and structure at the stern below the surface of the water. The wave resistance can also be reduced.

  In the above-mentioned ship with low wind pressure resistance, the stern side wall portion that forms the stern side of the structure on the water surface has a depth of unevenness of a maximum width B in plan view in the shape of each cross section parallel to the water surface. % Or less, or a straight line portion where the depth of unevenness is 5% or less of the maximum width B in a plan view, or a combination of both.

  By forming this smooth curved line or straight line with few irregularities, separation occurs in the flow at this curved part or straight part, and a large vortex that affects the resistance in question here. Can be prevented from occurring.

  In the above-mentioned ship with low wind pressure resistance, the stern side wall portion forming the stern side of the water surface structure is at least in the range of 0% to 50% in the vertical range of the water surface structure. It is formed so as to have an inclination angle θ3 of 30 deg to 90 deg with respect to the horizontal plane.

  By inclining the side wall portion on the stern side by 30 deg to 90 deg with respect to the horizontal plane, it is possible to suppress the eddy current generated at the corner portion between the stern side upper surface and the side wall portion forming the stern side of the structure on the water surface. Furthermore, by providing cornering or rounding at the corner between the stern side upper surface and the ship side wall, eddy current can be more effectively suppressed.

  Note that the above-described method for determining the structure of a ship with low wind pressure resistance can also be used as a design method for ships with low wind pressure resistance.

According to the ship having a low wind pressure resistance and the design method of the present invention, the wind pressure resistance can be reduced and the speed reduction can be improved. And the rudder can be suppressed, and speed performance and steering performance can be improved. As a result, fuel consumption and operational performance can be improved. In addition, since the wind pressure received in the port when detaching from the pier is reduced, the maneuverability in the port is improved, and the time required for the detachment can be reduced.

  In addition, when targeting an upper structure including a residential area, it is possible to suppress vortices generated by peeling behind this upper structure, so that smoke damage can be suppressed, and Safety and workability can be ensured.

It is the figure which looked at the superstructure of the ship in the 1st Embodiment of this invention from diagonally upward front. It is a side view of the upper structure of the ship of FIG. It is the top view which showed the stern side shape of the superstructure of FIG. It is the figure which looked at the ship in the 2nd Embodiment of this invention from diagonally upward back. It is the figure which looked at the ship of FIG. 4 from diagonally backward. It is a front view of the ship of FIG. It is a rear view of the ship of FIG. It is a right view of the ship of FIG. It is a left view of the ship of FIG. It is a top view of the ship of FIG. It is a bottom view of the ship of FIG. It is a figure which shows the stern side shape of the stern side part of the ship of FIG.

Hereinafter, embodiments of a ship having a low wind pressure resistance and a design method thereof according to the present invention will be described with reference to the drawings. Here, in the first embodiment, a ship having an upper structure of a residential area and a bridge provided above the upper deck will be described as an example, and in the second embodiment, an automobile-only ship will be described as an example. Explains. However, the present invention can be applied not only to an automobile-only ship but also to other ships such as a container ship, a tanker, and a passenger ship. In addition, in order to remove the ship that covers and covers the hull for stealth technology, the ship has a voyage speed V and a Froude number Fn related to the navigation speed V of the ship of 0.13 to 0.30. .

  Initially, the ship (henceforth a ship) with few wind pressure resistances of 1st Embodiment is demonstrated. As shown in FIGS. 1 to 3, in the marine vessel 1 according to the first embodiment, an upper structure (water surface structure) 12 is provided on an upper deck 11. The upper structure 12 has a bridge, dodgers 17 are provided on the left and right, and a chimney 18 is provided on the horizontal part 16 on the stern side of the upper structure 12.

  In the present invention, a fairing portion that forms a smooth flow is provided on the stern side of the upper structure 12 such as a bridge or a residential area. That is, the stern side shape of the upper structure 12 is formed by the side wall portions 13 and 14 and the horizontal portions 15 and 16 on the stern side, and the stern side shape of the upper structure 12 provided on the upper deck 11 is previously set. When moving forward in the set wind speed Vw at the voyage speed V of the ship 1, the vortex is not formed on the stern side of the upper structure 12. Whether or not a vortex is generated on the stern side can be easily verified by wind tunnel model experiments and numerical fluid simulations, and the specific shape is also the result of these wind tunnel model experiments and numerical fluid simulations. It can be easily determined from the known shape.

  The portion surrounded by the stern side walls 13 and 14 and the horizontal portions 15 and 16 may be used as a residential area or the like, but may be a gap. That is, the side wall portions 13 and 14 and the horizontal portions 15 and 16 may be formed as a cover body that surrounds a space so that vortex flow is not generated by the air flow on the stern side. Moreover, you may provide the opening part 13a in the side wall part 13 grade | etc., As needed on mooring.

  Instead of determining the specific shape from the results of wind tunnel model experiments, numerical fluid simulations, and the conventional known shapes, the shape of the stern side of the upper structure 12 is determined as follows. Also good.

  First, B is the maximum width excluding the dodger 17 and the support structure (not shown) of the dodger 17. Next, as shown in FIG. 3, the shape of the stern side of the upper structure 12 is set to at least 0% to 50%, preferably within the range of the height of the upper structure 12, that is, the range in the vertical direction. Is configured as follows in the shape of each cross section parallel to the water surface in the range of 0% to 70%, more preferably 0 to 100%. In other words, in the shape of each cross section parallel to the water surface in the range of 50% or more, preferably in the range of 70% or more, more preferably in the range of 100%, in the vertical range of the superstructure 12, The configuration is as follows. The height of the upper structure 12 does not include protrusions from the upper structure 12 such as a chimney or a mast.

  That is, in this range, the stern side rearmost portion of the maximum width B of the upper structure 12 is the lower side, the length B1 of the lower side is 0.9 × B, and the base angle θ1 is 40 deg to 80 deg, more preferably 50 deg to An isosceles trapezoid is made with 70 deg and the upper side length B2 of 0.5 × B. Further, an isosceles triangle having a stern side rearmost portion of the maximum width B as a base, a base length B3 of 1.2 × B, and a base angle θ2 of 40 deg to 80 deg, more preferably 50 deg to 70 deg is formed. And the shape of the stern side of this upper structure 12 is formed so that it may enter the area | region inside an isosceles triangle outside the area | region of this isosceles trapezoid in planar view.

  As for the height direction (vertical direction), it is preferable that there is no step because the flow of air smoothly flows and the generation of eddy currents is eliminated. However, when necessary in terms of structure, it is shown in FIGS. Thus, there may be a step in the height direction. In this case, it is preferable to provide chamfering or rounding at the corner of the stepped portion.

  With this configuration, it is possible to save time and effort for verification by wind tunnel model experiments and numerical fluid simulation, and it is possible to avoid the occurrence of a large vortex on the stern side with respect to the wind from the front.

  Note that if the angle of the base angle θ1 of the isosceles trapezoid is smaller than 40 deg, vortices are easily formed, and if it is larger than 80 deg, the stern side of the upper structure 12 is greatly extended in the stern direction. Similarly, if the angle of the base angle θ2 of the isosceles triangle is smaller than 40 deg, vortices are easily formed, and if it is larger than 80 deg, the stern side of the upper structure 12 is greatly extended in the stern direction.

  In addition, about the shape of this side wall part 13 and 14 at the stern side, it is preferable to form in the shape of each cross section parallel to a water surface in the shape of a smooth curve or a straight part in planar view. This smooth curve or smooth straight line is impossible for an actual ship to be completely free of irregularities. Therefore, it is preferable that the irregularities have a depth of 5% or less of the maximum width B. By forming it with a smooth curved line or straight line with few irregularities, it is possible to suppress the occurrence of a large vortex due to separation in the flow at the curved part or the straight part.

  Furthermore, the stern side walls 13 and 14 that form the stern side of the upper structure 12 are at least 0% to 50% within the range of the height of the upper structure 12, that is, the range in the vertical direction. In the shape of each cross section parallel to the water surface, preferably in the range of 0% to 70%, more preferably in the range of 0 to 100%, the following configuration is made. In other words, in the shape of each cross section parallel to the water surface in the range of 50% or more, preferably in the range of 70% or more, more preferably in the range of 100%, in the vertical range of the superstructure 12, The configuration is as follows. The height of the upper structure 12 does not include protrusions from the upper structure 12 such as a chimney or a mast.

  That is, in this range, it is preferable to form so as to have an inclination angle θ3 of 30 deg to 90 deg, preferably 50 deg to 70 deg with respect to the horizontal plane. With this configuration, it is possible to suppress the vortex generated at the corners between the stern side upper surfaces 15 and 16 forming the stern side of the upper structure 12 and the side wall portions 13 and 14 on the stern side. Furthermore, by providing cornering or rounding at the corner between the stern side upper surface and the ship side wall, generation of vortex can be more effectively suppressed.

  When the side walls 13 and 14 are formed in a curved surface shape in which the whole or a part of the upper side of the water surface is convex outward, the angle formed by the contact surface at each point on the curved surface with the horizontal surface is defined as an inclination angle θ3. To do. When the inclination angle θ3 is smaller than 30 deg, the lower portion of the upper structure 12 on the stern side greatly extends in the stern direction, and when it is larger than 90 deg, it becomes impractical.

  According to this configuration, the wind pressure resistance due to wind from the front is the largest when the vehicle moves forward in the preset wind speed Vw at the voyage speed V. At this time, the vortex (stagnation of the dead water region) If there is no vortex and Karman vortex outflow vortex, etc., the wind pressure resistance will be small. Can be reduced.

  Further, eddy currents are less likely to occur even when the wind is obliquely forward compared to the box-shaped upper structure of the prior art, and the wind pressure resistance of the upper structure 12 against the wind obliquely forward is reduced. Since the structure 12 is generally arranged on the stern side in consideration of cargo handling, the yaw moment due to the wind pressure is also reduced, so that the maneuverability is improved.

  Next, a ship (hereinafter referred to as a ship) with low wind pressure resistance according to the second embodiment will be described. As shown in FIGS. 4 to 13, the ship 1 </ b> A according to the second embodiment is an automobile exclusive ship, and in order to fix and convey the automobile from the bow of the hull 20 to the stern, The upper deck 21, which has a plurality of hierarchically structured decks, is provided with a mast 22 and a chimney 23, but is not provided with a bridge such as a bridge or a residential area. In this ship 1A, the bridge and the residential area are provided below the upper deck 21, and nothing protruding above the upper deck 21 is provided so as to reduce wind resistance.

  Further, below the water surface, a bow valve 31 is provided on the bow side, and a screw propeller 32 and a rudder 33 are provided on the stern side.

  In this configuration, for example, the bridge is provided on the bow portion that is well-viewed below the upper deck 21, and the residential area is provided on the stern side near the engine room with the engine. Recently, the engine control and inboard control have been made remote control, so the need to place the bridge, engine room, and residential area in the vicinity has also been reduced. Does not occur.

  An upward inclined surface 24 is formed on the bow from the upper end of the bow front edge toward the upper deck 21. The inclined surface 24 is formed so that the upward angle with respect to the horizontal plane is 20 deg to 60 deg, and preferably 38 deg. Thereby, when the flow of wind flows from the upper end of the bow front edge toward the upper deck, it is possible to suppress separation and vortex generation in the upper deck portion, and to reduce wind pressure resistance.

  A notch step 26 is provided at the corner formed by the upper deck 21 of the hull and both side portions 25 over almost the entire length from the bow to the stern. As shown in FIG. 6, the notch 26 is 5 to 20% of the freeboard fb in the ballast state obtained by subtracting the ballast draft db from the depth D from the upper deck to the bottom of the ship (the keel line) at the center of the hull. It is formed having a depth ds and a width bs. For example, it is formed by cutting out into a square shape with a width of one automobile to be loaded.

  The cut-out step 26 suppresses separation and vortex generation at the corner connecting the upper deck 21 and the heel side portion 25 with respect to wind in an oblique direction, thereby reducing resistance, lateral force, and yaw moment due to wind pressure. . The cut-out step 26 has a great effect when provided over almost the entire length from the bow to the stern, but it may be provided over a range from the bow to almost the center of the hull.

In the corner portion of the heel side portion 25 and the upper deck 21 of the notch step portion 26, it is preferable to provide an inclined surface 26a to reduce resistance when subjected to cross wind, and FIG. 4, FIG. 5, FIG. In the configuration of 10, the corners and the inclined surfaces are alternately arranged in the bow-stern direction. The inclined surface 26a is 30 deg to 60 deg, preferably 45 deg, and the height of the inclined surface 26a is preferably about two thirds to one third of the depth ds of the notch step portion 26.

  In the present invention, side walls 27 and 28 are provided as fairing portions that form a smooth flow in the stern side portion 20a of the portion of the hull 20 on the water surface (a structure on the water surface). In other words, the stern side shape of the stern side portion 20a is formed by the stern side wall portions 27 and 28 and the upper deck 21, and the shape of the stern side portion 20a is set in the wind speed Vw set in advance, and the voyage of the ship 1A. When moving forward at a speed V, the stern portion 20a is formed in a shape that does not generate vortex. Whether or not a vortex is generated in the stern side portion 20a can be easily verified by a wind tunnel model experiment or a numerical fluid simulation. It can be easily determined from a conventional well-known shape or the like.

  The portion surrounded by the side wall portions 27 and 28 and the upper deck 21 of the stern side portion 20a is arranged with a mooring device and a steering mechanism, but a gap portion may be provided. That is, you may form the side wall parts 27 and 28 and the upper deck 21 as a cover body which surrounds space so that a vortex | eddy_current may not generate | occur | produce with the flow of the air of the stern side. Moreover, you may provide an opening part in the side wall parts 27 and 28 as needed on mooring. In this configuration, an opening for a lampway and a door 29 for carrying a vehicle are provided. In addition, an opening for a lampway and a door 30 for carrying a vehicle are also provided on the side portion 25 near the center of the hull 20.

  Instead of determining the specific shape from the results of wind tunnel model experiments, numerical fluid simulations, and the conventional known shapes, the shape of the stern side of the stern side portion 20a is determined as follows. Also good.

  First, let B be the maximum width of the stern side portion 20a. The stern side portion 20a is set to the stern side from the end of the parallel portion of the hull 20, but when the end of the parallel portion is not clear, the stern perpendicular line A.1. P. To 0.2 × Lpp (length between perpendiculars) from the front position to the rear portion.

  As shown in FIG. 12, the shape of the stern side of the stern side portion 20a is at least 0% to 50%, preferably 0% to 70%, more preferably within the range of the stern side portion 20a in the vertical direction. The shape of each cross section parallel to the water surface in the range of 0 to 100% is configured as follows. In other words, in the range of the height of the stern side portion 20a, that is, in the range in the vertical direction, in the range of 50% or more, preferably 70% or more, more preferably 100%, parallel to the water surface. Each cross-sectional shape is configured as follows. Note that the height of the stern side portion 20a does not include protrusions from the upper deck 21 of the stern side portion 20 such as a chimney or a mast.

  That is, in this range, in the shape of each cross section parallel to the water surface, the stern side rearmost portion of the maximum width B of the stern side portion 20a is the lower side, the length B1 of this lower side is 0.9 × B, and the base angle θ1 Is 40 deg to 80 deg, more preferably 50 deg to 70 deg, and the upper side length B2 is 0.9 × B to form an isosceles trapezoid. Further, an isosceles triangle having a stern side rearmost portion of the maximum width B as a base, a base length B3 of 1.2 × B, and a base angle θ2 of 40 deg to 80 deg, more preferably 50 deg to 70 deg is formed. The shape of the stern side of the stern side portion 20a is formed so as to enter the region inside the isosceles triangle outside the isosceles trapezoidal region in plan view.

  With this configuration, it is possible to save time and effort for verification by wind tunnel model experiments and numerical fluid simulation, and it is possible to avoid the occurrence of a large vortex on the stern side with respect to the wind from the front.

  Note that if the angle of the base angle θ1 of the isosceles trapezoid is smaller than 40 deg, vortices are easily formed, and if it is larger than 80 deg, the stern side of the upper structure 12 is greatly extended in the stern direction. Similarly, if the angle of the base angle θ2 of the isosceles triangle is smaller than 40 deg, vortices are easily formed, and if it is larger than 80 deg, the stern side of the upper structure 12 is greatly extended in the stern direction.

  In addition, regarding the shape of the side wall portions 27 and 28 of the stern side portion 20a, the shape of each cross section parallel to the water surface is often formed by a smooth curved portion or a straight portion in plan view. Moreover, it is preferable to configure in this way. However, when the lampway door 29 is provided, it is impossible for the lamp 29 to be completely free of unevenness. Therefore, it is preferable that the depth of the unevenness be 5% or less of the maximum width B. By forming it with a smooth curved line or straight line with few irregularities, it is possible to suppress the occurrence of a large vortex due to separation in the flow at the curved part or the straight part.

  Further, the side wall portions 27 and 28 forming the stern side of the stern side portion 20a are set to have a height range of the stern side portion 20a, that is, at least 0% to 50%, preferably within the vertical range. The shape of each cross section parallel to the water surface in the range of 0% to 70%, more preferably 0 to 100%, is configured as follows. In other words, in the vertical range of the stern side portion 20%, in the shape of each cross section parallel to the water surface in the range of 50% or more, preferably 70% or more, more preferably 100%. The configuration is as follows. Note that the height of the stern side portion 20a does not include protrusions from the upper deck 21 of the stern side portion 20 such as a chimney or a mast.

  That is, in this range, it is preferable to form so as to have an inclination angle θ3 of 30 deg to 90 deg, preferably 50 deg to 70 deg with respect to the horizontal plane. With this configuration, it is possible to suppress the vortex generated at the corners between the upper deck 21 and the side wall portions 27 and 28 that form the stern side of the stern side portion 20a.

  When the side walls 13 and 14 are formed in a curved surface shape in which the whole or a part of the upper side of the water surface is convex outward, the angle formed by the contact surface at each point on the curved surface with the horizontal surface is defined as an inclination angle θ3. To do.

  The side wall portions 27 and 28 are preferably formed in a curved shape in which the whole or a part of the upper side of the water surface is convex outward. In this case, the contact surface at each point on the curved surface is a horizontal plane. The formed angle is defined as an inclination angle θ3. Furthermore, by providing cornering or rounding at the corners of the upper deck 21 and the side wall portions 27 and 28, generation of vortex can be more effectively suppressed.

  When the inclination angle θ3 is smaller than 30 deg, the lower portion of the stern side portion 20a is greatly extended in the stern direction, and when it is larger than 90 deg, it becomes impractical.

  According to this configuration, the wind pressure resistance due to wind from the front is the largest when the vehicle moves forward in the preset wind speed Vw at the voyage speed V. At this time, the vortex (stagnation of the dead water region) If there is no vortex and Karman vortex outflow vortex, the wind pressure resistance will be reduced, so the wind pressure will be lower than the transom stern shape of the conventional stern side wall that extends in the left-right direction throughout the voyage. Resistance can be reduced.

  In addition, eddy currents are less likely to occur even when the wind is obliquely forward compared to the shape of the stern of the ransom type of the prior art, and the wind pressure resistance of the hull 20 against the wind obliquely forward is reduced. Since the moment is also reduced, the maneuverability is improved.

The ship with low wind pressure resistance and its design method of the present invention can reduce wind pressure resistance and improve ship speed reduction, and can improve speed performance and maneuverability, resulting in improved fuel efficiency and operational performance. Since it can be improved, it can be used as many kinds of ships, and in particular, it can be used for automobile ships, container ships, and passenger ships with a large wind pressure area .

1, 1A Ship 2 Water surface 11, 21 Upper deck 12 Upper structure (structure on water surface)
13, 14 Side wall part (fairing part)
15, 16 Horizontal portion 17 Dodger 20 Hull 20a Stern side portion of the hull surface structure (water surface structure) 21 Upper deck 25 Saddle side portion 26 Notch step portion 27, 28 Inclined portion 29, 30 Lampway opening B2 Maximum width B1 Length of the lower side of the isosceles trapezoid B2 Length of the upper side of the isosceles trapezoid B3 Length of the base of the isosceles triangle Vw Wind speed V Navigation speed θ1 Bottom angle of the isosceles trapezoid θ2 Bottom of the isosceles trapezoid Angle θ3 Angle of inclination of side wall with respect to horizontal plane

Claims (4)

The stern side shape of the upper structure on the upper deck or the stern side of the hull on the water surface in a ship with a voyage speed and a fluid number related to the navigation speed of the ship of 0.13 to 0.30. The shape of the structure on the water surface of at least one of the following shapes is set to the stern side when moving forward in the preset wind speed at the nautical speed, at a position behind the stern vertical line by a distance of 0.2 × the vertical line. In a shape that does not generate a vortex that has a diameter from three times the maximum width of the structure on the water surface to one tenth of the maximum width,
In the shape of the structure on the water surface ,
In the case of an upper structure having a bridge, when the maximum width excluding the dodger and the support structure of the dodger is defined as B, the shape of the stern side of the structure on the water surface is set in the vertical direction of the structure on the water surface. In the shape of each cross section parallel to the water surface in the range of at least 0% to 50% of the range,
An equilateral leg with the stern side rearmost part of the maximum width B as the lower side, the lower side length B1 being 0.9 × B, the base angle θ1 being 40 deg to 80 deg, and the upper side length B2 being 0.5 × B From an isosceles triangle in a range outside the trapezoid and having the stern side rearmost portion of the maximum width B as the base, the length B3 of the base is 1.2 × B, and the base angle θ2 is 40 deg to 80 deg A ship with low wind pressure resistance, characterized in that it is also formed to enter the inner region . The side wall portion on the stern side that forms the stern side of the structure on the water surface has a smooth curved shape in which the depth of the unevenness is 5% or less of the maximum width B in plan view in the shape of each cross section parallel to the water surface. The ship with low wind pressure resistance according to claim 1, wherein the ship is formed by a part, a straight part where the depth of the unevenness is 5% or less of the maximum width B in a plan view, or a combination of both . The side wall portion on the stern side that forms the stern side of the water surface structure has an inclination of 30 deg to 90 deg with respect to the horizontal plane in a range of at least 0% to 50% of the vertical range of the water surface structure. The ship with low wind pressure resistance according to claim 1 or 2, wherein the ship has an angle θ3 . The speed of the stern of the hull on the water surface, which is the shape of the stern side of the hull on the water surface, is a preset wind speed. The maximum width of the maximum width of the structure on the surface of the water is 3 times the maximum width of the structure on the water surface at a position behind the stern vertical by 0.2 × the length between the vertical when moving forward at the voyage speed. In a shape that does not generate eddy currents with a diameter of up to 1/10,
In the shape of the structure on the water surface,
In the case of an upper structure having a bridge, when the maximum width excluding the dodger and the support structure of the dodger is defined as B, the shape of the stern side of the structure on the water surface is set in the vertical direction of the structure on the water surface. In the shape of each cross section parallel to the water surface in the range of at least 0% to 50% of the range,
An equilateral leg with the stern side rearmost part of the maximum width B as the lower side, the lower side length B1 being 0.9 × B, the base angle θ1 being 40 deg to 80 deg, and the upper side length B2 being 0.5 × B From an isosceles triangle in a range outside the trapezoid and having the stern side rearmost portion of the maximum width B as the base, the length B3 of the base is 1.2 × B, and the base angle θ2 is 40 deg to 80 deg A design method for a ship with low wind pressure resistance, characterized in that it is formed so as to enter the inner region.