JP7473622B1 - Ships - Google Patents

Abstract

[Problem] To provide a ship with reduced resistance to wind obliquely coming from the front of the bow. [Solution] In a ship (1) equipped with a bow windscreen (3) at a bow (2) and a superstructure (5) on a deck (4), a wind guide (6) having a guide surface that receives wind from the front of the bow and guides the wind above the superstructure (5) is provided on the deck (4) between the bow windscreen (3) and the superstructure (5). The wind guide (6) is a structure shaped like a triangular pyramid, one of three faces of which is the guide surface (6A) that faces obliquely forward relative to the bow direction, and a pair of left and right wind guides are installed on the deck. When wind from the oblique front of the bow passes over the side wall of the bow windscreen (3) and enters the deck (4), the wind is guided by the guide surface (6A) of the wind guide (6) and directed above the superstructure (5), thereby reducing wind resistance. [Selected Figure] Figure 1

Description

The present invention relates to a ship. More specifically, it relates to a ship with a wind pressure reduction structure.

Air resistance on a ship is caused by the hull itself, and by the superstructure above the hull. It is known that reducing this air resistance can significantly reduce fuel consumption. The superstructure here refers to the accommodation space located in the forward part of the deck and the structure above it, such as the wheelhouse.

The air resistance of car carriers and other vessels is greater for hulls with a large frontal area than for superstructures. However, from the perspective of the number of cars that can be carried and space to install various pieces of equipment, it is more rational in ship design to try to reduce air resistance to the superstructure without changing the shape of the hull.
Therefore, in order to reduce the air resistance to the above-mentioned structures, the conventional techniques disclosed in Patent Documents 1 and 2 have been proposed.

The conventional technology of Patent Document 1 is to install a resistance member for controlling the air flow on the deck, forward of the bow side of the superstructure.
This conventional technology is said to be able to suppress separation of air flow around the superstructure, thereby reducing air resistance acting on the superstructure.
However, although it is possible to guide wind from the front of the hull above the superstructure, it is not possible to deal with wind coming from diagonally forward, so the effect of reducing wind pressure is not sufficient.

The prior art of Patent Document 2, as shown in Figure 5 (A), is a configuration in which a bow windscreen 3 is provided at the bow 2 of a ship 1, and a ship equipped with a superstructure 100 on a deck 4 has an intermediate windscreen 121 provided in front of an intermediate accommodation space 111 that constitutes the superstructure 100. The superstructure 100 is made up of the intermediate accommodation space 111 and the uppermost accommodation space 112.
In this conventional technology, the bow windscreen 3 and the middle windscreen 121 work together to guide the wind wf from the front of the bow above the topmost living area 112 as shown by the arrow wf, thereby reducing the wind resistance to the superstructure 100.

The inventors discovered that the above-mentioned conventional technology is effective in reducing resistance to wind wf coming from directly in front of the bow, but is ineffective against wind wd coming from diagonally ahead of the bow. To find out why, the inventors analyzed the airflow around the bow based on computational fluid dynamics, and found that wind wd, which passes over the side of the bow windscreen and enters the deck, first descends onto deck 4 but then rises again, at which point it strikes the front of the accommodation space 100. In this way, when wind strikes the front of the superstructure 100, it naturally creates wind resistance.

JP 2001-328587 A JP 2010-111209 A

In view of the above circumstances, the present invention aims to provide a ship that reduces resistance to wind coming diagonally forward of the bow.

The ship of the first invention is a ship equipped with a bow windscreen at the bow and a superstructure on the deck, characterized in that a wind guide is provided on the deck between the bow windscreen and the superstructure, the wind guide having a guide surface that receives wind that enters the deck from diagonally forward of the bow, over the side wall of the bow windscreen , and guides the wind above the superstructure.
The ship of the second invention is characterized in that, in the first invention, the wind guide is a structure shaped like a triangular pyramid, and one of the three faces is oriented diagonally forward relative to the bow direction as the guide surface.
The ship of the third invention is the ship of the second invention, characterized in that the wind guides are installed on the deck, one on each side, between the bow windscreen and the superstructure.

According to the first aspect of the present invention, when wind from the diagonal front of the bow passes over the side wall of the bow windscreen and enters the deck, the wind is guided by the guiding surface of the wind guide and directed above the superstructure, so that the wind from the diagonal front does not collide with the front wall of the superstructure, thereby reducing wind resistance.
According to the second invention, since the wind guide is a triangular pyramid, if the wind is coming from the diagonal front, the wind can be guided by the guide surface even if the direction changes considerably, and wind coming from directions other than the diagonal front can be allowed to escape without resistance.
According to the third aspect of the present invention, the pair of wind guides on the left and right sides are provided, so that the wind pressure reducing effect can be achieved for both wind from the right side and wind from the left side obliquely forward.

1 is a perspective view of a bow portion of a ship provided with a wind guide 6 according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the arrangement of the wind guide 6 shown in FIG. 1 . 1A is a front view of the air guide 6, and FIG. 13 is a graph showing the wind pressure reduction effect. 1A and 1B are explanatory diagrams of Patent Document 2, in which (A) is an explanatory diagram of the wind pressure reducing effect for wind from the front, and (B) is an explanatory diagram of the problem for wind from diagonally ahead.

Next, an embodiment of the present invention will be described with reference to the drawings.
A wind pressure reduction concept for a boat 1 according to one embodiment of the present invention will be described with reference to FIGS.
In Figures 1 and 2, reference numeral 1 denotes a ship such as a car carrier or a RORO ship, and only the bow portion is shown in the figures.
A bow windscreen 3 is provided on the upper part of the bow 2 of the ship 1. The bow windscreen 3 is a deflector plate erected around the deck of the bow 2, and is provided to deflect wind from the front upward.

A superstructure 5 is provided on the deck 4 of the ship 1. The superstructure 5 includes a living area 5A and a wheelhouse 5B. In the illustrated example, the superstructure 5 has a two-story structure, but is not limited to this, and a structure having three or more stories is also included in the present invention.
The superstructure 5 is located on the deck 4 immediately aft of the bow windscreen 3 .
The term "aft" used here refers to the rear of the ship, based on the fore-and-aft direction, with the bow in front and the stern in the rear.

A wind guide 6 is installed between the bow windscreen 3 and the superstructure 5. Here, the area between the bow windscreen 3 and the superstructure 5 is in front of the superstructure 5, and includes both the area surrounded by the bow windscreen 3 and the area aft of the end of the bow windscreen 3.

The wind guide 6 in this invention is a structure with a guide surface that receives wind from diagonally forward of the bow and guides it above the superstructure 5. Any structure with a guide surface may be used, but in one embodiment of the present invention, a triangular pyramid structure is used.

As shown in (A) and (B) of FIG. 3, the wind guide 6 has a bottom plate in the shape of an equilateral triangle, and the three side plates 6a, 6b, and 6c are in the shape of an isosceles triangle, forming a triangular pyramid. One of the three side plates can be positioned so that it functions as the guide surface 61 shown in FIG. 2.

The wind guide 6 can be attached to the deck 4 by any method, such as bolting or welding. The attachment direction to the deck 4 may be fixed or variable. To make it variable, a seat plate is used, and the seat plate is fixed to the deck 4 by bolting or the like, and the wind guide 6 can be fixed so that it can rotate in a horizontal plane relative to the seat plate and face a specific direction. Such a direction-changeable attachment can be achieved, for example, by providing multiple bolt holes and passing bolts through any of the bolt holes and fastening them.

There are no particular restrictions on the material of the wind guide 6, and any material can be used, such as metals such as steel or aluminum plates, plastic, or wood.

As shown in Figure 1, when wind wd from diagonally ahead of the bow passes over the side wall of the bow windscreen 3 and enters the deck 4, the wind wd is guided by the guiding surface 61 of the wind guide 6 and rises, becoming wind wu guided above the superstructure 5. As a result, the wind wd from diagonally ahead does not collide with the front wall of the superstructure 5, reducing wind resistance.

Since the wind guide 6 is a triangular pyramid, if the wind wd comes from the diagonal front, the guide surface 61 can guide the wind even if the direction changes considerably, and it can allow wind from directions other than the diagonal front to escape without resistance. And, by having a pair of wind guides 6 on the left and right, it can reduce the wind pressure of the wind wd coming from the diagonal front, both from the right and left sides.

(Example)
Examples of the present invention will be described below together with comparative examples.
Example 1 is a model ship of the ship 1 having the structure shown in Figures 1 to 3, and uses a bow windscreen 3 and a wind guide 6. For the 1/125 scale model, the wind guide 6 is a triangular pyramid with a height of 24 mm (which is "100% of the height of the accommodation area 5A") and a base of 34 mm (which is "140% of the length of the height of the accommodation area 5A").
Comparative Example 1 was the same as Example 1 except that the wind guide 6 was not used. Comparative Example 2 was the same as Example 1 except that the wind guide 6 and the bow windscreen 3 were not used.

For the above-mentioned Example 1, Comparative Example 1, and Comparative Example 2, wind resistance was measured by a wind tunnel experiment using a model ship. In this experiment, the guiding surface 61 of the wind guide 6 was changed between -45° and +45° with respect to the wind. The results are shown in FIG.
In this case, in FIG. 4, the horizontal axis represents angles ranging from −45° to +45° with the front of the ship being 0°, and the vertical axis represents the wind resistance coefficient (Cx).

The wind resistance coefficient Cx is expressed by the following formula.
Cx = Fx / (1/2 ^ρSV2 )
(Fx: Measured wind resistance ρ: Air density S: Frontal projection area V: Representative wind speed)
In other words, it shows how much wind resistance the model ship experiences when the wind resistance of a flat plate with the same area as the frontal projected area of the model ship is taken as 1. The lower the wind resistance, the lower the value.

As can be seen from the graph in Figure 4, Comparative Example 2 (no bow windscreen or wind guide) has the highest resistance, Comparative Example 1 (with bow windscreen, no wind guide) has the next highest resistance, and Example 1 has the lowest resistance.
In Example 1, wind pressure resistance caused by wind coming from diagonally ahead (especially at 20 degrees and 30 degrees) is particularly reduced, and the wind pressure reduction efficiency is reduced by 4.7% when the diagonal wind is 20° and by 4.5% when the diagonal wind is 30° compared to Comparative Example 1.
From the above results, it is understood that the wind guide 6 according to the present invention has a remarkable effect in reducing wind resistance caused by wind coming from the oblique front.

1 Ship 2 Bow 3 Bow windscreen 4 Deck 5 Superstructure 6 Wind guide

Claims (3)

In a vessel equipped with a bow windscreen at the bow and a superstructure on the deck,
A ship characterized in that a wind guide having a guide surface is provided on a deck between the bow windscreen and the superstructure for receiving wind that enters the deck from diagonally forward of the bow, over the side wall of the bow windscreen , and guides the wind above the superstructure. 2. The ship according to claim 1, wherein the wind guide is a triangular pyramid-shaped structure, one of three faces of which is oriented diagonally forward with respect to the bow direction as the guide surface. 3. The ship according to claim 2, wherein the wind guides are provided on the deck, one on each side, between the bow windscreen and the superstructure.