JPS6013106A - Structure of waterfall - Google Patents

Abstract

PURPOSE:To prevent the occurrence of noise originated from the shaking of waterfall curtains by laying plural stones in parallel at a given distance on the upstream side from the falling port edge of a falling port plate. CONSTITUTION:A falling port plate 2 is attached to the upper part of a falling port 1, and plural stones 3 are laid in parallel at a distance of (d) on the upstream side from the falling port 2a of the plate 2. The stones 3 of a flat square plate form are fixed such that their diagonal angular portions coincide with the flowing direction of water, and an interval of d1 is provided between the adjacent stones. The flowing speed of water is increased in the section 4 between the stones 3 but decreased in the section 5 on the downstream side of the stones 3, and the flat form of the waterfall curtain W becomes wave form wholly because the faster portion of the flowing water is expanded forwards. The occurrence of noise originated from the shaking of the waterfall curtain W can be prevented since continuous phenomenon caused by the surface tension or viscosity of the fluid is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a waterfall structure that prevents unpleasant noises caused when a water curtain falls.

For example, at a waterfall (including an dam) as shown in Figure 1.2, conventionally, when the water curtain falls from the droplet F, it sounds like the sound of a small motor. There were times when I heard a continuous unpleasant sound like banging. When we observed this phenomenon in detail, we found that when the water curtain falls, the water curtain W swings in a wave-like manner as shown in Figure 1, and when this swing is viewed from the front, it shows a horizontal movement due to the wave motion as shown in Figure 2. Unfortunately, this vibration caused the above-mentioned "flapping" sound. Therefore, if the abnormal vibration of the falling water curtain can be eliminated, the generation of the above-mentioned unpleasant noise can be prevented.

An object of the present invention is to prevent unpleasant noises caused by abnormal swings of falling water curtains.In order to achieve the above object, various methods have been tried.

First, we tried changing the shape of the drop opening in various ways, as shown in Figures 3 to 5. That is, in Fig. 3, an iron plate P is attached to the droplet F over the entire width, and the tip Pa of this iron plate is inclined downward by 45, and in Fig. 4, the tip Pbt is tilted upward by 45.
In FIG. 5, the tip end Pct was cut into a tooth shape (square wave shape) and was tilted downward by 45'. However, in none of the examples was it possible to eliminate the abnormal phenomenon of the water curtain. Second, as shown in Figure 6.7, half of the droplet F is dammed up by the weir plate P1, and the thickness of the water curtain W is changed from 15 to 2.
I tried making it as thick as 3 tones, but the above abnormal phenomenon could not be eliminated in this case as well.

In this way, experiments were conducted by changing the shape of the waterfall's opening and the thickness of the water curtain, but in each case the water curtain swayed and an unpleasant sound was produced.

It was found that this wave of the water curtain does not occur when there is no wind. When the wind was artificially generated and the wind was applied to the water curtain, the water curtain swung again and horizontal stripes appeared. This swing is
It was also found that it can occur even with a slight breeze, and that once it occurs, it continues for a certain period of time.

From the above, the problem of the present invention can be solved if the falling water curtain of the waterfall is not affected by the wind, and as a result of the experiment,
I found the solution below.

The solution to this problem is to place multiple arms such as stones or concrete blocks in parallel in the width direction of the waterfall at a certain distance from the rim of the waterfall upstream from the edge of the waterfall. For this reason, the flow speed of water becomes faster between the arms and falls from the droplet, and slows down downstream where the arms are opposite and falls.In this way, the water curtain has a faster flow rate moving forward. bulge,
It does not form a single strip, but forms a wave with regular bulges, which prevents a continuous phenomenon due to the surface tension or viscosity of the fluid, and as a result, prevents the formation of horizontal stripes that occur in the water curtain due to wind. Ru. The predetermined distance from the rim of the droplet to the mass is a range in which the water curtain does not form a single band shape but can form a wavy shape.

An embodiment of the present invention will be described below with reference to FIG. 8.9.

The waterfall has a height of about 1m, a width of about 10m, and a volume of water of 3ooo.
The droplet plate 2 is mounted on the droplet 1 at z/m.

Upstream side from the drop edge 2a of this drop plate (right side in Figure 1)
A plurality of stones 3 are arranged side by side with a distance d between them. This stone is 40 x 40 x 20 considering the design.
It is a rectangular stone plate with a thickness of (my) and made of the same material as the drop plate 2. Each stone 3°... is fixed on the droplet plate 2 so that its diagonal corners match the direction of water flow (vertical direction in Figure 2), and the distance d from the droplet edge 2a is It is about 100m.

Each stone 3... is the distance dt between adjacent stones (Figure 2)
is approximately 1001, and is installed horizontally in a straight line across the width of the droplet.

With this configuration, the water flow is faster Dk in the flowing water part 4 between the stones 3, and the water flow is faster Dk in the flowing water part 5 on the opposite side of the stones.
As shown in FIG. 2, the planar shape of the water curtain W is such that the water curtain bulges forward in the portion where the flow velocity is high, so that the bulging portion 6 forms a waveform as a whole. The most desirable waveform for the water curtain is when the apex 4a of the fast-flowing water portion 4 reaches the drop edge 2a as shown in FIG. This was the most effective way to prevent runout.

Note that the stone may be a natural stone cobblestone, and if the stone is heavy, it is sufficient to simply place it directly on the droplet, and it is not necessarily necessary to fix it to the droplet. Further, when both the distance d and the interval d were set to 200 m, no effect was found.

As explained above, according to the present invention, the water curtain does not form a single strip, but instead becomes a waveform with thick and thin thickness, so that the continuous phenomenon caused by the surface tension or viscosity of the fluid is closed, and as a result, wind It is possible to prevent the noise caused by the shaking of the water curtain. Moreover, the generation of unpleasant noise can be prevented with a simple configuration and low cost.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional front view showing the structure of a conventional waterfall, Figure 2 is a left side view of Figure 1, and Figures 3 to 5 are droplets in various experimental examples in which the shape of the droplet was changed. Figure 6 is a cross-sectional front view of the droplet in an experimental example in which the thickness of the water screen was varied, Figure 7 is a cross-sectional view taken along the line ■-■ in Figure 6, and Figure 8 is an embodiment of the present invention. FIG. 9 is a sectional front view showing an example, and FIG. 9 is a left side view of FIG. 8. 1... Drop opening, 2... Drop opening plate, 3... Stone, 4.
・・・Flowing water flowing between 6, 4a...Apex of flowing water, 5
... flowing water flowing on the opposite side of the stone, 6... bulge, d.
・・Distance from the edge of the pit to the stone, d, ・・Interval, W・
...Water curtain. Figure 1 Tail 2 Figure 4 Horse Figure 6

Claims (1)

[Scope of Claims] fl) Arms made of a plurality of stones, concrete blocks, etc. are installed on the droplet at a predetermined distance upstream from the rim of the droplet, and these arms are attached to the droplet. They are arranged in parallel in the width direction, and the predetermined distance is such that the water S can form a waveform due to the difference between the flow velocity of the water flowing between the arms and the flow velocity on the opposite downstream side of the arms. Waterfall structure. (2) A waterfall structure according to claim 1, characterized in that the arms are installed at a position where the apex of the fast flowing water flowing between the arms reaches the edge of the drop opening.