JPH04334691A - Resistance reducing device for marine vessel - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drag reduction device for a ship, which recovers the rotational energy of a propeller and at the same time reduces the viscous pressure resistance acting on the ship's hull.

0002

2. Description of the Related Art Recently, in ships, propellers 3 are installed on both port and starboard sides of the stern part 2 of the ship body 1, as shown in FIG.
The rectifying plate 5 is horizontally extended so as to be located near the axis 4 of the rectifying plate 5 and is approximately parallel to the water line 6.
As a result, the upward flow 7 from the stern bilge section 2a and the downward flow 8 from the stern flare section 2b are regulated and rectified in the axial direction. A system has been proposed that can reduce the pressure loss caused by the upward flow 7 and the downward flow 8, restore the pressure on the stern hull surface, and effectively reduce the hull viscous pressure resistance, and an application has already been filed. (Patent Application No. 2-86396).

On the other hand, as another energy saving measure, as shown in FIGS. 4 and 5, the profile of the stern section 2 of the hull 1 is curved at the most constricted position so as to protrude from the hull centerline 10 to the port side. A plate-shaped aperture fin 11 is provided,
It is also known that the aperture fins 11 can generate a rotating flow in the direction opposite to the rotational direction of the propeller to improve propulsion efficiency.

0004

[Problems to be Solved by the Invention] However, in the case of the system shown in FIG. Although it is possible to effectively reduce the viscous resistance of the hull 1 by recovering the rotational energy of the propeller 3, no consideration is given to efficiently recovering the rotational energy of the propeller 3.

On the other hand, in the case of the systems shown in FIGS. 4 and 5, the aperture fin 11 can create a rotational component opposite to the rotational flow behind the propeller in front of the propeller, thereby reducing rotational energy loss of the propeller. Although it is possible to improve the propulsion efficiency of ships by
When the aperture fin 11 is attached, the surface pressure on the port side of the stern section 2 increases and the surface pressure on the starboard side of the ship decreases, so there is a problem that a lateral force FL that tends to bend the hull 1 to the left acts. In order to make the hull 1 go straight, it is necessary to use a counter rudder, which reduces the effect of recovering rotational energy.

[0006] Therefore, the present invention aims to provide a drag reduction device for a ship that can reduce viscous pressure resistance and improve the propulsion performance of the ship by taking advantage of the aperture fins. .

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present invention has a structure in which the profile at the stern end of the hull is curved near the hull centerline at the most constricted position so as to protrude to the port side. Aperture fins are attached, and a rectifier plate is attached to the starboard side of the stern section, extending parallel to the water line.

[0008]

[Function] Propulsion efficiency can be improved by the aperture fins, and viscous pressure resistance can be reduced by the rectifying plates. A lateral force is generated due to the presence of the aperture fins, but this is canceled out by the lateral force generated by the pressure increase on the rectifying plate side.

[0009]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show an embodiment of the present invention, in which the profile of the two ends of the stern section of the hull 1 is located near the hull centerline 10 (see FIG. 5) at the most constricted position, and the port side A plate-shaped aperture fin 11 that is curved so as to protrude is attached, and a rectifying plate 5 is installed on the starboard side of the stern section 2 so as to be located near the axis 4 of the propeller 3 and approximately parallel to the water line 6. Install it by extending it.

When the hull 1 is sailed with a plate-shaped aperture fin 11 curved toward the port side attached to the vicinity of the hull center line 10 at the end of the stern part 2, a rotational flow opposite to the rotational direction of the propeller 3 is transmitted to the propeller 3. The rotational energy loss of the propeller 3 can be reduced. At this time, due to the presence of the aperture fin 11, the balance of the port and starboard pressure distributions is disrupted, as shown in FIG.
A lateral force FL is generated that tries to bend the hull 1 to the left, but
The rectifying plate 5 attached to the starboard side can generate a lateral force FR in a direction that cancels the lateral force FL. That is, since the rectifier plate 5 is attached to the starboard side of the stern section 2, the stern vortex can be weakened, thereby increasing the pressure on the rectifier plate 5 side, reducing viscous pressure resistance. , the lateral force FR generated by the above pressure increase
The lateral force FL caused by the aperture fin 11 can be canceled by. Therefore, the hull 1 can be made to go straight without using a counter rudder, and at this time, the effect of improving the propulsion efficiency by the aperture fin 11 and the effect of reducing viscous pressure resistance by the baffle plate 5 can be obtained at the same time.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[0013]

As described above, according to the drag reduction device for a ship of the present invention, the aperture fin that is curved so as to protrude to the port side is attached near the hull center line at the stern end, and the rectifying plate is attached to the stern end. Since the structure is such that the fins are installed parallel to the waterline on the starboard side of the fin, the lateral force generated by the aperture fin can be canceled out by the lateral force generated by the rectifying plate. The propeller's rotational energy recovery effect can be increased, and the aperture fins can improve propulsion efficiency and the rectifier plate can reduce viscous pressure resistance, improving propulsion performance. It can produce excellent effects.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of a drag reduction device for a ship according to the present invention.

FIG. 2 is a view taken along the line AA in FIG. 1;

FIG. 3 is a schematic diagram showing an example of a recently proposed drag reduction method for ships.

FIG. 4 is a schematic diagram showing another example of a conventional ship drag reduction method.

FIG. 5 is a view taken along the line B-B in FIG. 4;

[Explanation of symbols]

1 Hull 2 Stern part 5　Brectifier plate 6 Water line 10 Hull center line 11 Aperture fin

Claims (1)

[Claims] Claim 1: An aperture fin curved to protrude to the port side is installed near the hull center line at the point where the profile at the stern end of the hull is the most constricted, and a water line is provided on the starboard side of the stern. 1. A drag reduction device for a ship, characterized in that it has a configuration in which a rectifier plate is attached that extends in parallel with the current plate.