JPS61225420A - Water stream damping structure - Google Patents

Abstract

PURPOSE:To stabilize the stream of water on the downstream side by reducing the dynamic water pressures by a method in which a shield plate is provided on the downstream side of a gate provided on the downstream side of a channel head work in such a way as to make the water level on the downside lower than that on the downstream side and also a stream-smoothing plate is provided. CONSTITUTION:A gate 4 capable of securing a cross section of water stream not to produce a head on the water surface of the upstream side is provided on the downstream side of a water channel head work 3. A shield plate 6 whose downside is positioned at a lower place than the water level of the downstream side and incapable of giving free surface to the overflow water 8 of the gate is provided on the downstream side of the gate 4. A lattice-like stream- smoothing plate 7 for the effluent stream 8 of the gate is provided on the lower part of the plate 6.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a water flow energy reducing structure in a waterway drop.

<Prior art> Conventionally, when there is a large height difference between the upstream and downstream sides of a waterway, there is a risk that the flowing water will be accelerated and affect the downstream area, so a drop structure was installed in the middle of the waterway to reduce the water flow. It is designed to reduce the energy of

<Problems to be solved by this invention> In such a drop structure, the dynamic pressure generated when the water veins falling through the drop structure collides with the bottom of the channel is significantly greater than the hydrostatic pressure, and structural reinforcement measures are required. In addition, since the water veins after falling flow down at high velocity along the waterway bottom, countermeasures against abrasion of the subgrade material are required.Furthermore, the high-speed flow causes water jumps that cause turbulence on the water surface on the downstream side. There are other problems.

This invention was proposed to solve these problems, and its purpose is to reduce the dynamic water pressure acting on the waterway bottom by suppressing and rectifying the significant turbulence of the water flow that occurs in the drop structure, and further reducing the water flow downstream. An object of the present invention is to provide a water flow reducing structure capable of stabilizing side flow.

<Means for Solving the Problems> The water flow energy reduction structure according to the present invention has a gate installed on the downstream side of the waterway drop structure to ensure a cross-sectional area of water flow so that no head difference occurs in the water surface on the upstream side. And downstream of this gate,
A blocking plate is provided whose lower surface is located at a position lower than the downstream water level to prevent a free surface from being provided to the flow flowing out of the gate, and a rectifying plate is provided to rectify the flow flowing out of the gate. It suppresses significant turbulence in the water flow and straightens it, and roughly stabilizes the flow on the downstream side using a blocking plate and a rectifier plate.

<Example> The present invention will be described below based on an illustrative example.

As shown in FIG. 1, a drop 3 is provided between the upstream waterway 1 and the downstream waterway 2, and on the downstream side of the drop 3, a gate 4, an outlet 5, a blocking plate 6, and a rectifier are installed in order. A plate 7 is provided.

The function of the gate 4 is to eliminate or reduce the head of the drop structure 6 caused by the difference in water level between the upstream waterway 1 and the downstream waterway 2. , the water level on the upstream side of the gate is secured depending on the relationship between the downstream water level. As a result, significant turbulence in the water flow generated in the drop 3 is suppressed and the water flow is rectified.

The shielding plate 6 is positioned such that its lower surface 6A is lower than the downstream water level and higher than the opening height of the gate 4, so as not to provide a free surface to the gate outflow flow 8, and to block air and water. ing. When the flow directly under the gate 4 flows out due to the difference between the water level upstream of the gate and the water level downstream, it becomes a high-speed flow, which prevents air from being drawn in and significantly disturbing the flow downstream of the gate.

The rectifying plates 7 are grids arranged vertically and horizontally (see FIG. 3), and two rectifying plates 7 are provided at the lower part of the blocking plate 6 to rectify the flow 8 flowing out from the gate. That is, the purpose is to prevent the generation of high-speed flow as described above and the flow velocity distribution in the downstream water depth from becoming non-uniform, and at the same time, it is possible to cause energy loss due to the shape.

<Effects of the Invention> As mentioned above, according to the present invention, it is possible to reduce the energy of water flow by simply adding existing gates, shielding plates, and rectifying plates to the drop structure, and it is possible to reduce the force of the water flow with a relatively simple configuration. No special structural reinforcement measures or anti-wear measures for subgrade materials are required.

Further, the flow on the downstream side can be stabilized.

Furthermore, the gate opening degree and the number of rectifier plates can be selected depending on the flow rate. Note that even if the flow rate fluctuates, it can be handled by making the gate opening variable.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a side sectional view and a plan sectional view showing a water flow energy reducing structure according to the present invention, and FIG. 6 is a front view showing a rectifying plate. 1. Upstream waterway, 2. Downstream waterway, 3. Drop work,
4...gate, 5...outlet, 6...blocking plate, 7...straightening plate, 8...gate outflow flow. Thatch 1 Figure 4 Plant

Claims (1)

[Claims] (1) Install a gate on the downstream side of the canal drop that can secure a cross-sectional area of the water flow so that there is no difference in the water level on the upstream side, and install a gate on the downstream side of this gate at a position where the lower surface is lower than the water level on the downstream side. 1. A water flow reducing structure, characterized in that a blocking plate is provided so as to prevent a free surface from being provided to the flow flowing out from the gate, and a rectifying plate is provided to rectify the flow flowing out from the gate.