JPH0370671B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stern rectifying structure provided to rectify the flow in the stern of a ship and introduce it to a propeller.

The conventional stern rectifying structure is shown in Fig. 1 (side view of the stern), Fig. 2 (longitudinal cross-sectional view along the hull centerline of the conventional stern rectifying structure), and Fig. 3 (- in Fig. 2).
As shown in the cross-sectional view shown in FIG. 3, a shew piece 4 is installed between a rudder support member 5 that supports the rudder 3 and the lower end of the stern frame.

The show piece 4 includes a plurality of vertical plate members 6.
The front end of the plurality of vertical plate members 6 is fixed to the lower end of the stern frame 2, and the rear end is fixed to the rudder receiver 5.

Further, the plurality of rectifying plates 7 are installed between the vertical plate members 6 at appropriate mutual intervals, rising and tilting rearward, and are fixed to each of the vertical plate members 6 at a substantially right angle.

In a ship equipped with such a show piece 4, when the screw propeller 1 rotates and the ship is sailing, the water near the show piece 4 flows rearwards from below the stern bottom 2b. However, since the flow passes between the vertical plate member 6 and the straightening plate member 7, it flows into the rotating surface of the screw propeller without being substantially disturbed and without slowing down the flow.

Therefore, the flow velocity distribution at the propeller position becomes more uniform than in the case where the show piece 4 is not formed to have a rectifying structure.

However, in the case of the conventional flow straightening structure as described above, the flow velocity is slowed down near the hull centerline C by the stern bottom portion 2b.

That is, FIG. 4 is a graph showing the results of measuring the flow velocity distribution at an arbitrary radius within the propeller rotation circle in a cross section of the screw propeller position of a ship. In the stern rectification structure of , the flow velocity decreases directly below the propeller (in the center of the hull), which is directly above the shew piece.

In this way, according to the conventional stern shape,
The flow velocity is slowed down by the stern bottom 2b near the hull centerline C, and the flow velocity distribution within the cross section at the propeller 1 position becomes uneven, causing thrust and moment fluctuations in the propeller 1, causing propeller vibration. There is a problem in that it becomes a force and causes the hull to vibrate.

The present invention aims to solve these problems, and by providing a recess in the center of the hull and stern frame near the shew piece, the flow velocity distribution at the propeller position is made uniform, and the propeller excitation force is reduced. It is an object of the present invention to provide a stern rectification structure that reduces hull vibration by reducing the vibration of the ship.

Therefore, the stern rectification structure of the present invention includes a plurality of vertical plate members arranged at appropriate intervals in the ship width direction to connect the lower rear end of the stern hull and the rudder receiver below the stern tube. and a plurality of straightening plates installed at appropriate mutual intervals between the longitudinal plate members and raised and tilted rearward. A recess is provided in the hull, the recess becomes larger as it goes from the lower part of the stern tube to the bottom of the ship, and the front edges of the vertical plate members on both sides of the shew piece are connected to both ends of the recess, respectively. Additionally, the front edge of the vertical plate member inside the showpiece extends to and is connected to the inner surface of the recess.

An embodiment of the present invention will be described below with reference to the drawings. Figures 4 to 6 show a stern rectification structure as an embodiment of the present invention, Figure 4 is a graph showing its characteristics, and Figure 5 is the hull of the ship. FIG. 6 is a longitudinal sectional view taken along the center line, and FIG. 6 is a sectional view taken along the - arrow in FIG.

As shown in FIGS. 1, 5, and 6, below the stern tube 2a, an appropriate section is installed in the width direction to connect the lower part of the rear end of the stern frame 2 constituting the stern hull with the rudder receiver 5. A plurality of vertical plate members 6 are arranged at intervals.

That is, the ends of the plurality of vertical plate members 6 are fixed to the lower rear end of the stern frame 2, and the rear ends are fixed to the rudder receiver 5.

A plurality of rectifier plates 7 are installed between the vertical plate members 6 so as to be appropriately separated from each other.

This rectifying plate member 7 is provided so as to be inclined upwardly to the rear, and is fixed to each vertical plate member 6 at a substantially right angle.
The flow below the stern bottom 2b is guided to the rotating surface of the propeller 1.

In this way, the show piece 4 is formed by the vertical plate member 6 and the rectifying plate member 7.
supports the rudder 3 attached to the rudder support member 5 and rectifies the flow flowing into the propeller 1.

On the other hand, in the stern frame 2 that constructs the stern hull,
A recess 11 is provided along the hull centerline C from near the bottom of the stern tube 2a to the bottom of the ship.

This recessed portion 11 has both rear ends 9, 9
The depth from the stern tube 2a to the front end 8 is formed to gradually increase from the lower part of the stern tube 2a to the bottom of the ship. The leading edges are connected to each other.

Further, within the recess 11, a vertical plate member 6 provided in the show piece 4 extends, and the front edge of the vertical plate member 6 is connected to the inner surface of the recess 1. 7 is installed so that a part of the flow below the stern bottom 2b is rectified in the recess 11 and guided to the rotation surface of the propeller 1.

Since the stern rectification structure of the present invention is configured as described above, when the hull 10 is running, the stern bottom part 2
The flow near b flows through both outside sides of the shew piece 4 and the vertical plate member 6 and rectifying plate member 7 inside the shew piece 4.
is guided along the plane of one revolution of the propeller.

Further, a part of the flow passes through the recess 11, is rectified by the vertical plate member 6 and the rectifying plate member 7 in the recess, and is guided to the rotating surface of the propeller 1 without causing a flow velocity and bottom drop.

Since the recess 11 is provided along the hull centerline C, the flow passing through the recess 11 is mainly guided directly below the propeller 1.

Therefore, the flow velocity distribution on the rotating inner surface of the propeller 1 becomes uniform as shown by the broken line B in FIG.

As described in detail above, according to the stern rectification structure of the present invention, the stern tube is arranged at an appropriate interval in the ship width direction to connect the lower rear end of the stern body and the rudder receiver below the stern tube. A shew piece is provided, which is made up of a plurality of vertical plate members installed in the stern tube and a plurality of flow velocity plates installed at appropriate intervals between the longitudinal plate members and raised and tilted rearward. A recess is provided in the stern hull near the hull centerline, and the recess becomes larger as it goes from below the stern tube toward the bottom of the ship, and the front edges of the longitudinal plate members on both sides of the shew piece are connected to the recess, respectively. It has a simple configuration in which the front edge of the vertical plate member inside the shew piece is connected to both sides of the rear end of the shew piece and extends to the surface of the recess, thereby making the flow field at the propeller position uniform. This reduces propeller excitation force, which has the advantage of reducing hull vibration.

[Brief explanation of drawings]

Figure 1 is a side view of the stern of a ship;
Figures 2 and 3 show the conventional stern rectification structure.
Fig. 2 is a longitudinal sectional view taken along the centerline of the hull, Fig. 3 is a sectional view taken along the - arrow in Fig. 2, and Figs. 4 to 6 show a stern rectification structure as an embodiment of the present invention. Figure 4 is a graph showing its characteristics, Figure 5 is a longitudinal cross-sectional view along the hull center line, and Figure 6 is a graph showing its characteristics.
It is a sectional view taken along the - arrow in the figure. DESCRIPTION OF SYMBOLS 1... Propeller, 2... Stern aggregate, 2a... Stern tube, 2b... Stern bottom, 3... Rudder, 4... Shew piece, 5... Rudder receiving material, 6... Vertical plate member, 7
. . . Current plate material, 8 . . . Front end of the recess, 9 . . . Rear end of the recess, 10 . . . Hull, 11 .

Claims (1)

[Claims] 1. Below the stern tube, a plurality of vertical plate members are arranged at appropriate intervals in the ship width direction to connect the lower rear end of the stern hull and the rudder receiver, and appropriate intervals are placed between the longitudinal plate members. A recess is provided in the stern hull near the hull center line from near the bottom of the stern tube to the bottom of the ship. A recess is formed to become larger from the lower part of the stern tube toward the bottom of the ship, and the front edges of the vertical plate members on both sides of the shew piece are connected to the rear ends of the recess on both sides, and the A stern rectification structure characterized in that a leading edge of the vertical plate member extends to and is connected to the inner surface of the recess.