Research On Hydraulic Characteristics In Flexible Vegetation Channel

It is universal to plant vegetation in compound cross section watercourse. According to experiments, the hydrophyte has good effect on getting rid off some severe pollute material, to plant some particular plants can purify the water. The plants also can protect the side bank besides this. But the vegetation in watercourse also brings some problems. For example, the aquatic vegetation increase the resistance of the bed, raise the water level, decrease the velocity of water and convert the power of water into turbulent energy, it can also lower the flow of watercourse. So men have high attention on the vegetation in watercourse now.We will research on the impact of the flexible vegetation in watercourse, as follows:1. A three-dimensional-acoustic Doppler velocimeter is used to measure the velocity, turbulence intensity, Renolds stress, resistance in vegetated condition and none-vegetated condition in bottomland region, main channel region and their adjacent region. We can also find out some rules from the experiment in different flow.2. We put the tracer material into the watercourse to measure the distance for the water from the bottomland returning into the main channel, and find the relationship between flow and the distance for water returning into the main channel.3. We compare the open channel experiment data with the former data after planted flexible vegetation. From these we find the disturbance for dense vegetation is greater than thin vegetation.