JPS6042187A - Vessel - Google Patents

Abstract

PURPOSE:To suppress production of bow wave and to reduce the wave crush resistance by arranging symmetrical blades in the vicinity of draft line at the bow and cancelling the bow wave vortex with the tip vortex produced by said blade. CONSTITUTION:A symmetrical triangular blade having streamline cross-section is fixed in the vicinity of draft line 4 to the hull 5 while stretching forward and to the left/right of bow 1. The back/fro position and the width of the blade 3 are set such that the blade end 6 will come near to the front edge 7 of crush wave region to be produced under advancing of hull. Upon advance of hull 5 in the direction (i), circulation flow is produced around the cross-section of blade 3 and isolated from the blade end 6 to produce the tip vortex. Since the rotary direction of tip vortex 13 is reverse of the rotation of crush wave vortex 14, they will interfere to cancel the crush wave vortex 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ship designed to reduce wave-breaking resistance generated by bow-breaking waves.

As the ship moves forward, the pressure of the water surrounding the bow increases, causing the water surface to swell and generate six waves.

-C1 This bow wave is caused by the hull a, which has a relatively small entry angle θ as shown in Figures 1 and 2, and has a high ship speed, or by the enlarged hull shape as shown in Figures 3 and 4. In the case of a ship with a rounded bow, such as hull C, the wave crest collapses forward, generating so-called bow-neck vortices or wave-breaking vortices d and e, and this vortex and the backflow of the broken waves cause In addition to creating wave-breaking resistance equivalent to loss of momentum, air bubbles caught in the vortex and caught in the bottom of the ship reduce propeller efficiency and cause cavitation, among other problems.

Furthermore, as shown in Figures 2 and 4, the generation range of wave-breaking vortices d and c, that is, the leading edge lines f and g of the wave-breaking region, are closer to the bow as the shedding angle is smaller, and the rotation of the vortex Regardless of the shape of the bow, the starboard side faces forward with a right-hand thread, and the port side faces with a left-hand thread.

Since wave-breaking resistance accounts for a considerable portion of the hull resistance, it is necessary to reduce wave-breaking resistance as much as possible. For ships traveling at high speed, the shedding angle θ can be
I'm making it smaller.

However, the above countermeasures [) cannot completely prevent bow wave breakage, and the cutting angle cannot be reduced in a swollen ship, so there is a strong need to establish effective countermeasures.

The present invention was made to solve the above-mentioned problems.
This relates to a ship configured such that symmetrically formed wings are arranged near the water line at the bow of the ship so that wing tip vortices generated in the water by the wings cancel out wave-breaking vortices at the bow. This suppresses the swelling of the water surface, which reduces the occurrence of bow breaking waves, and also reduces the tip vortices (
Since the wave-breaking vortex (or horse vortex) interferes with and cancels out the wave-breaking vortex, wave-breaking resistance can be significantly reduced, which has the advantage of saving energy in ship operation.

Embodiments of the present invention will be described below with reference to the drawings. 5 to 8 show a first embodiment of the present invention, in which reference numeral 1 is a wedge-shaped bow, 2 is the center of the hull,
A triangular wing 3 having a symmetrical streamlined cross section is attached to the hull 5 almost horizontally or at an appropriate elevation angle so as to surround the bow 1 near the water line 4 and protrude in front of the bow and on both left and right sides. The longitudinal position and wing span of the wing 3 are located near the leading edge line 7 of the wave breaking area that occurs during forward movement of the ship, as Iff@6.6 will be described later.
is set to .

Next, the function of the blade 3 will be explained. When the jet 3 moves along with the hull 5 in the direction of the arrow i as shown in FIG. The water flow on the upper surface of the wing is accelerated and the water pressure is reduced. Therefore, the swelling 12 of the water surface in front of the bow 1 is suppressed. Also, the circulation 1o is the blade tip 6.6
The blades are separated from each other to generate wing tip vortices 13, 13, and extend into the water toward the rear of the hull 5. Breaking vortex 1 in the rotational direction of the blade tip vortex 13
4, the blade tip vortex 13 and the wave-breaking vortex 14 interfere with each other, eliminating or reducing the wave-breaking vortex 14. Therefore, breaking wave resistance is significantly reduced and hull resistance is reduced.

Next, a second embodiment of the present invention is shown in FIGS. 9 to 11. This example shows application to a swollen hull 5a such as a tanker.
The position and wing span of the shield 3a are such that the wing tips 6a, 6a are near the leading edge line 7a of the wave breaking area, as described in the first embodiment. The height and angle of attack of the blades 3a are set in the same manner as in the first embodiment.

Next, the functions of the blade 3a and the vertical plate 16 used in this embodiment will be explained. As the hull 5a moves forward, a boundary layer 11 is formed on the surface of the vertical plate 16 as shown in FIG. A dead area 19 occurs at the bow attachment part of the ship. Therefore, around the vertical plate 16,
A flow similar to that in the case where a small virtual cutting angle θ1 (see the two-dot chain line) is attached to a right-handed wedge-shaped bow is formed, and 13a exerts the same effect on this flow as in the first embodiment. Cover the bow to reduce breaking waves.

Next, a third embodiment of the present invention is shown in FIGS. 12 and 13. In this example, the wing 3b and the vertical plate 16a are mounted on a hull 5b having a bow valve 21, and the wing 3b
b The functions of A3 and the vertical plate 16a are the same as in the second embodiment.

Next, a fourth embodiment of the present invention is shown in FIGS. 14 and 15. In this example, the retreated M3C is attached to the n-neck overhang part 24 of the enlarged hull 5c via the strut 22, so that the leading edge 25 of the wing almost coincides with the leading edge line 7b of the wave-breaking area. In addition, the angle of attack α is set such that the leading edge 25 of the blade is appropriately raised relative to the trailing edge 28 in the flow direction j so as to effectively suppress the generation of bow waves.

The action of the JH wing 3G in this embodiment is the same as that of the containers 3, 3a, and 3b described so far, and there is no need to repeat the same explanation, but the bow wave suppressing action is the same as the previous one. Let's break away from the theory and explain it in simple terms. 01 below the waterline when the ship moves forward and overturns
) The water pressed against the neck rises to the water surface and moves to form an imaginary bow wave 29 shown by a two-dot chain line.

On the other hand, water flowing into R3C from the horizontal direction is deflected by M3C and moves to form waves 30 (not shown by dotted lines). The waves actually generated are the two waves 29, .
30 (indicated by a solid line), and the wave height is significantly reduced.

If the wing is supported using the A-bar hang part of the bow of the ship mentioned above, the same I
M m can be used to install a wing that reduces wave-breaking resistance (=I).

In the above explanation, the blade cross section is streamlined and the blade shape is shown as a triangular or swept blade, but the threshold cross section is a flat plate shape.
Alternatively, the blade shape may be rectangular or other shapes.

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

Since the ship of the present invention relies on the above-described configuration, it exhibits the following excellent effects.

(+) The wings are symmetrically formed and placed near the bow waterline, and the wing tip vortex cancels bow breaking waves, suppressing the generation of bow waves and reducing wave breaking resistance. .

(Ii) As a result of item (0), the hull resistance is reduced, and the main engine output and fuel consumption can be reduced.

As a result of the OiO term (1), the propeller efficiency decreases due to the wax bubbles caught in the bottom of the ship due to the bow ship's 1' wave.
This prevents pitation and navigation malfunction, and also makes the wake less noticeable, making stealth operations easier.

00 The same applies to newly built ships and ships already in service.

[Brief explanation of drawings]

Figures 1 to 4 show the occurrence of bow-breaking vortices in conventional ships, and Figures 1 and 2 show the wedge-shaped bow,
Figure 3 J3 and Figure 4 are explanatory diagrams of the enlarged ship shape;
5 to 8 show a first embodiment of the present invention, FIG. 5 is a partial side view of the hull, and FIGS. 6 and 7 are Vl-V1 direction and vi-vnh direction in FIG. 5. Fig. 18 is an explanatory diagram of the circulation occurring around the wing, Figs. 9 to 11, Figs. 12 and 13, and Figs. 2nd, 3rd,
The fourth embodiment is shown, and FIG. 9 is a partial side view of the hull;
Figures 0 and 11 are views taken from the X-X direction and XI-XI force direction in Figure 9, Figure 12 is a partial side view of the hull, and Figure 13 is a view taken from the xm-xmh direction in Figure 12. 14 is a partial side view of the hull, and FIG. 15 is a view taken in the direction of the xv-xv force in FIG. 14. In the figure, 1 is a wedge-shaped ship m, 3, 3a, 3b, 3c are wings, 4 is a water line, 5.5a, 511, 5C is a hull, 15
indicates the bow perpendicular. Patent application: Ishikawajima Jlli Heavy Industries Co., Ltd. Figure 2 Figure 5 Figure 7 Figure 4 Continued from page 1 Inventor Takashi Sahara 0 Inventor Takashi Tsutsumi 1 Shin-Nakahara-cho, Isogo-ku, Yokohama Ishikawajima-Harima Heavy Industries Co., Ltd. Technical Research Center

Claims (1)

[Claims] 1) A ship characterized in that symmetrically formed wings are arranged in the vicinity of the water line at the bow, so that the wing tip vortices generated in the water do not cancel out the bow wave-breaking vortices due to the gaps.