Trapezoidal Channel Water And Sediment Movement Characteristics Of Plant Growth

The paper is supported by the Chinese National Natural Science Foundation (No.50769001),which is the interaction mechanism study on the water flow, sediments, pollutants and plants of the wetland of altiplano lake. The flexible and rigid simulated plants are applied to the research program. This paper especially studies the impact that the flexible and rigid simulated plants exert on flow structure in trapezoidal open flume.Based on the flume experiment in the lab, this paper emphasizes on the flow structure in trapezoidal open flume without plant covered. The results is that the max velocity of flow lies on the symmetric line of the trapezoidal open flume, the maximum point is in some position of relative water depth's 75% to 85%, not in the free surface of the liquid. Different height green plastic grasses are used as the flexible simulated plants and analyze the flow characteristic of the trapezoidal open flume with the flexible simulated plants. It comes to a conclusion that the flow velocity's vertical distribution is separately researched below the plant canopy and above one with the submerged grasses. By drilling the holes on the bottom of the trapezoidal open flume, choosing synthetic glass sticks in the different diameter as the rigid simulated plants, analyzes the flow characteristic of the trapezoidal open flume with the rigid simulated plants. The conclusion is that the flow of velocity in the major trough is more than in the side slope and the maximum of the sectional velocity lies on the boundary between the major trough and the side slope. The transverse distribution of velocity results from the superposition of flow around many circular cylinders. Additionally, the paper sets forth the definition of the length which is the two sides slope flow of the plant dam converges on the major trough. The definition of the length reflects on the change that is worked by the simulated plants in the trapezoidal open flume. In order to study the fixing and trapping sediment mechanism with the plant covered in the flume, the experiment of sanding the flume is designed. The results show that the plants dam can not only block water, trap sediment but prevent movement of sand, make the plentiful sand deposits on the downstream position of the vegetable dam. The appearance that the sand from two side slope moves on the boundary is visible. There are two sand ripples and ridges shaped on the boundary.Based on model of the surface of the tracking VOF RNGκ-εand the numerical simulation of the method was applied, the condition that under the flow of 10.31L/s just for rigid simulated vegetations with diameter of 16mm is computed. The result of computed and experiment is inosculated.