JPH01190809A - Wave elimination device - Google Patents

Abstract

PURPOSE:To effectively crush incident waves by continuously providing vertical plates around a horizontal plate so as to form a boxlike structure whose lower end is opened. CONSTITUTION:Vertical plates 3 are continuously provided around a horizontal plate 2 so as to constitute a boxlike structure 1 whose lower end is opened. And a plurality of openings 9a, 9b are formed in the vertical partition walls 8a, 8b, and when a pressure change in an air layer 6 is caused by waves, the waves are eliminated. Further, the boxlike structure 1 is installed in the bottom of the sea 4 so as to produce a flow in the reverse direction to incident waves behind the vertical plates 3. Thus, incident waves can be effectively crushed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a wave canceling device that eliminates wave energy by reflecting and absorbing it.

<Prior Art> Various wave-dissipating devices have been proposed to ensure safe harbor waters. These are generally breakwater structures (breakwaters) in which structures and obstacles are fixed or stacked on the seabed, and are designed and constructed according to the geology of the seabed, water depth, etc. The structure is such that the wave-blocking effect or wave-dissipating effect is achieved.

<Problems to be Solved by the Invention> However, with such conventional wave dissipating devices, large reflected waves are generated at the front of the breakwater, for example, which receives the incident waves, which becomes an obstacle to ship navigation, and as the water depth increases, construction Expenses increase. Furthermore, since such a breakwater is established on the seabed, there are problems such as a poor seawater exchange rate between the front and back parts of the breakwater.

In addition, recently, in order to make more effective use of coastal areas facing the open sea, there has been an increasing need for wave-dissipating structures that have a seawater exchange function, have good wave-dissipating efficiency, and are highly economical.

This invention was made in view of the problems and needs of the prior art, and provides a wave dissipating device that suppresses the generation of reflected waves, does not cause deterioration of the seawater exchange rate, and can be obtained at low cost with a simple structure. The purpose is to obtain.

<Means for Solving the Problems> The wave dissipating device according to the present invention has a box-like structure with an opening at the bottom, which is composed of a horizontal plate and a vertical plate connected around the horizontal plate, at a predetermined depth from the water surface. It was installed underwater.

The box-like structure of the present invention reflects and breaks waves in the amplitude direction by the horizontal plate, and generates a flow in the opposite direction to the incident wave behind the structure by the vertical plate, and this flow is It acts to dissipate waves by colliding with the incident waves. In addition, if an air layer is provided within the box-like structure, the crests of the waves are suppressed depending on the thickness of the air layer, and the troughs of the waves are pushed up, thereby smoothing out the wave height as a whole. It acts like this.

<Embodiments of the Invention> Examples of the invention will be described below with reference to the drawings. 1st
The figure is a sectional view showing one embodiment, and FIG. 2 is a perspective view as well. In the figure, J is a box-like structure, which is composed of a horizontal plate 2 and a vertical plate 3 connected to the periphery of the horizontal plate 2, and the lower end thereof is open downward. Moreover, this box-like structure 1 is fixed on a plurality of pillars 5 erected on the seabed 4 so as to be located underwater at a predetermined depth from the water surface.

Further, an air layer 6 is provided within this box-like structure 1, and this is in contact with a water surface 7 adjacent to the air layer while maintaining an appropriate relative pressure. 8a and 8b are reinforcing vertical partition walls provided to separate the air space 6 in the box-like structure 1, and the partitions P and Q
, R, and two or more rows may be provided as necessary. 9a, 9b are a plurality of openings formed in the vertical partitions 8a, 8b, which allow air to move to each compartment P, Q, R when the pressure of the air layer 6 changes due to waves; It functions to dissipate waves. Further, 10 is a vertical reinforcing plate in which an air layer 6 separated by vertical partition walls 8a and 8b is provided in a direction crossing the direction of wave propagation. Note that the openings 9a, 9b on the vertical partition walls 8a, 8b are provided in the direction of wave propagation.

Next, the effect will be explained.

Now, when a wave is traveling in the direction of arrow A, the horizontal plate 2 reflects the wave in the amplitude direction and causes the reflected wave to collide with the incident wave in the opposite direction, as shown in Fig. 3. , breaking waves. On the other hand, the vertical plate 3 generates a flow behind the box-like structure 1 in the direction opposite to the incident wave (direction D), which is transferred to the horizontal plate 3.
By guiding the wave to the top of the waveguide and causing it to collide with the incident wave, the incident wave is broken and a wave-dissipating action is performed.

Furthermore, since an air layer 6 is provided inside the box-like structure 1, when the wave A arrives, the air in the air layer 6 of the compartment P located directly under the crest of this wave will increase the water pressure. It rises with. Therefore, as shown in FIG. 4, the air passes through the opening 9a of the vertical bulkhead 8a to the compartment Q, which is a low-pressure air layer 6, and then passes through the opening 9b of the vertical bulkhead 8b to the compartment R.
escape to. Therefore, the air layer 6 directly below the wave crest becomes thinner, and acts to lower the water surface of the wave crest by that much. On the other hand, the air layer 6 in the compartment R located directly below the wave trough becomes thicker, contrary to the above, and acts to push up the water surface in the wave trough, and as a result, the wave height on the horizontal plate 2 is the same as the solid line. It is smoothed from . to the state shown by the one-dot chain line. In this way,
The air layer 6 further ensures the wave-dissipating effect.

FIG. 5 shows the wave-dissipating effect according to the present invention based on experimental results, and the vertical axis shows the incident wave height Hi and the transmitted wave height Ht.
The transmittance K t (Ht/Hi) is taken. Here, it is shown that the smaller kt is, the higher the wave dissipation effect is.

In addition, the horizontal axis shows the ratio B/L of the width of the wave absorber, that is, the width of the box-like structure 1 (length in the direction of propagation of the incident wave) B to the incident wavelength.
I took it.

From this experimental result, this wave canceling device can be used to
It can be seen that the wave height can be reduced to 1/2 or less with a width of about 1/6.

Furthermore, when an air layer 6 is provided within the box-shaped structure 1,
As shown in the figure, it can be seen that the wave-dissipating effect is even higher than when it is not provided.

<Effects of the Invention> As explained above, according to the present invention, a box-like structure with an opening at the lower end consisting of a horizontal plate and a vertical plate connected thereto is configured to be installed underwater. Incident waves can be effectively broken by the waves reflected by the horizontal plate and vertical plate, and the flow generated behind the box-like structure by the vertical plate can be caused to collide with the incident wave, thereby being extinguished. The wave effect can be further ensured. In addition, when an air layer is provided within a box-like structure,
Since changes in water pressure caused by the height of waves are alleviated by the movement of air in the air layer, the wave height can be further smoothed, and the advantage is that the wave dissipation effect is further improved. Since such a box-like structure has a simple shape and structure as a whole, it can reduce construction costs and has extremely high practicality.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the entire wave-dissipating device according to the present invention;
Figure 2 is an enlarged perspective view, Figure 3 is an explanatory diagram showing the wave-absorbing effect of this invention, Figure 4 is an explanatory diagram further showing the wave-absorbing effect of an air layer, and Figure 5 is an experimental result of this invention. It is a characteristic graph showing. 1. Box-like structure, 2. Horizontal plate, 3. Vertical plate, 6.
・Air layer.

Claims (1)

[Claims] 1) A fire extinguisher characterized in that a box-like structure with an opening at the bottom, consisting of a horizontal plate and a vertical plate continuous to the periphery of the horizontal plate, is installed underwater at a predetermined depth from the water surface. wave device. 2) The wave dissipating device according to claim 1, characterized in that an air layer is provided inside the box-like structure. 3) Claim 1, characterized in that the inside of the box-like structure is divided into a plurality of compartments by vertical partitions, and these compartments are communicated through openings provided in each of the vertical partitions. Wave dissipating device as described in section.