JPS58156489A - Stern flow straightening fin - Google Patents

Abstract

PURPOSE:To straighten a flow in the stern to an optimum state in accordance with a loaded condition, by dividing a flow straightening fin of the stern in the longitudinal direction of a ship while turnably mounting each divided fin in the vertical direction to a ship body through hinges. CONSTITUTION:A stern flow straightening fin A is divided in the longitudinal direction of a ship, and both ends of each fin 12, 13, 14, 15 are supported to parts 18 of a ship body by hinges 16, 17, then each pin can be rotated around these hinges 16, 17. Further the center of each fin is connected to an oil hydraulic cylinder 20 through a hinge 19, and each fin is rotated by this cylinder 20 to change an angle formed by each fin and ship body outer panel 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for rectifying the flow in a stern ferry. In general, ships not only sail with a full load, but also sail with a light load. The stern wharf changes momentarily as the loading conditions change. For this reason, as shown in Figures 1 and 2, the fixed fins l attached to the stern section 2 can, for example, effectively rectify the flow at the stern and reduce the propeller excitation force in a fully loaded state. , when the load was light, the flow at the stern could be disturbed and have the opposite effect (Figure 1 is a side view of the stern,
FIG. 2 is a sectional view taken along the arrow I in FIG. 1, where 8 is a propeller and 4 is a rudder.

bond 5 indicates the water surface, 6 indicates the hull shell, and 10 indicates the propeller shaft).

In order to overcome these drawbacks, a stern rectifier fin has been proposed in which the inclination of the fin in the longitudinal direction can be changed in response to changes in the wharf caused by changes in loading conditions.

These are shown in FIGS. 8 to 6.

8 is a side view of the stern section, and FIG. 4 is a sectional view taken along the line N-IV in FIG. 8. The fin la changes the inclination of the fin 1a in the front-rear direction by rotating around the fin 1a. That is, the fin 1a is connected to the hinge 7 of the fin 1a.
The rear end of the fin 1a is connected by a hinge 8 to a support rod 9 that moves up and down.

By moving this support rod 9 up and down, it is possible to change the inclination of the fins 1a. 17 However, since such a movable fin la needs to be able to move on the complex curved surface of the stern without creating a gap between the surface of the hull outer plate 9 and the fin 1m, the length of the fin 1g is too long. The drawback was that the length could not be increased. FIGS. 5 and 6 show a structure in which such restrictions on the length of the fins la are removed. The fin is divided into two parts, and the slope of each fin Ib and lc changes.

Figure 5 is a side view of the boat's seed part, and Figure 6 is the IV of Figure 5.
- [V is a sectional view taken along the arrow. Each fin lb, lc
are supported by a rotating shaft 11 protruding from the hull outer plate 6 at the center of each, and can rotate around the rotating shaft 11. fin lb
, lc are connected to a sliding device tta for setting the mounting angle. The inclination of each fin lb, lc is changed by moving the sliding device 11a up and down. however.

If the inclinations of the fins lb and lc are changed, the gap (step) between the front end of the fin lb and the rear end of the fin lc will increase, and the flow near the fins lb and lc will not flow away smoothly. was there.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a stern rectifying fin designed to effectively rectify the flow at the stern in any loading state.

For this reason, the stern rectifier fin of the present invention is provided on the side wall of the ship from above the propeller at the stern section to in front of the propeller, and divides the stern rectifier fin 7 in the ship's direction in the stern rectifier fin that equalizes the flow flowing into the propeller. With,
It is characterized in that each of the divided fins is attached to the hull via a hinge so as to be freely rotatable in the vertical direction.

An embodiment of the present invention will be described below with reference to the drawings. Fig. 7 is a side view of the stern section of a ship equipped with a stern rectifying fin (hereinafter referred to as the main fin), and Fig. 8 is a side view of the stern section of a ship equipped with a stern rectifying fin (hereinafter referred to as the main fin). Arrow sectional view, Figure 9 is the 7th
It is a sectional view taken along the line IX-IX in the figure. Components in the figure that are the same as those in FIGS. 1 to 6 are given the same reference numerals.

This fin A is composed of a plurality of fins.

Each fin 12.18, 14.15 is hinged at both ends.
6. '17 is supported on part 18 of the hull by these hinges ta, t? The center of each fin 12 to 16 is connected to a hydraulic cylinder 20 via a hinge 19. Therefore, as this cylinder 20 expands and contracts, each fin 12 to 1
5 rotates around hinges 16 and 17, and the fins 12 to 5 rotate around hinges 16 and 17.
15 and the hull outer plate 6 (FIG. 9) can be changed.

Next, its effect will be explained.

For example, the flow flowing into the propeller 3 when the propeller is fully loaded and no fins are attached is shown by the dotted line in FIG. Here, Wx on the vertical axis is the wake coefficient, Wx=1-Vx/V
(Vx: Flow velocity in the direction of the propeller shaft 10.

V: ship speed), θ is the rotation angle around the propeller axis lO, and 00 is taken directly above the propeller. Further, the wake distribution in the circumferential direction where r7R (r: radius around the propeller axis, R: propeller radius) is 1.1 is shown as a representative.

On the other hand, when the present fin A is attached as shown in FIG. 7, the wake distribution changes as shown by the solid line 1', the flow near θ-Qo increases and the wake coefficient decreases.

Therefore, the wake coefficient WX in the θ direction changes gradually, and the propeller excitation force is reduced.

On the other hand, when sailing with a light load, the wake distribution when no fins are attached is shown by the dotted line in FIG. On the other hand, when the present fin/A is installed as shown in FIG. 7, the wake distribution becomes as shown by the solid line, and the wake coefficient Wx at θ=0° decreases.

Wx near θ-800 is increasing. Overall, the wake distribution is not necessarily uniform.

Therefore, if the present fin A is in the state shown by the solid line in FIGS. 12 and 13, that is, the angle a is increased.

The wake distribution changes from the dotted line in Fig. 11 to the dashed-dotted line, the flow hermitage near θ-00 to 80° increases, and the change in the wake coefficient Wx in the θ direction becomes gradual, increasing the propeller excitation force. It can be reduced. In addition, Figures 12 and 13
In the figures, dotted lines indicate the position of the main fin A in FIGS. 7-9. Moreover, FIG. 18↓ is a sectional view taken along arrows XI-XI in FIG. 12.

As described above, according to the stern rectifying fin of the present invention, by adjusting the mounting posture of the fin in response to the stern flow that occurs as the loading condition changes, the optimum rectification for each loading condition is achieved. This has the advantage that the propeller excitation force can be reduced.

[Brief explanation of drawings]

1 to 6 show the stern of a ship equipped with conventional stern rectifying fins, and FIG. 1 is a side view. Fig. 2 is a sectional view of the door in Fig. 1 taken from the Soya arrow, Fig. 8 is a side view corresponding to Fig. 1, Fig. 4 is a sectional view taken from the ■-IV arrow of Fig. 8, and Fig. 5 is a sectional view taken from the 1 is a side view corresponding to FIG. 1, FIG. 6 is a sectional view taken along the line Vl-Vl in FIG. Something. Fig. 7 is a side view thereof, Fig. 8 is a cross-sectional view taken along the line II-II arrow in Fig. 7, Fig. 9 is a cross-sectional view taken along the IX-IX arrow in Fig. 7, and No. 1O~
Figure 11 is a graph showing the effects of this example, and Figure 12 is a graph showing the effects of this example.
The side view corresponding to the figure, Figure 18 is X-XI of Figure 12.
It is an arrow sectional view. 2... Stern section, 8... Propeller, 4... Rudder, 5...
・Water surface, 6... Hull outer plate, 10... Propeller shaft, 1
2-15...Fin, 16,17.19...Hinge. 20...Hydraulic cylinder, A...Stern rectifying fin. spear 1

Claims (1)

[Claims] It is provided on the side wall of the ship from above the propeller at the stern section to the front thereof, and flows into the propeller. In the stern rectifying fin that equalizes the flow, the stern rectifying fin is divided in the ship's direction. A stern rectifying fin characterized in that each of the divided fins is attached to a hull via a hinge so as to be freely rotatable in the vertical direction.