Research Of Hydraulic Characteristics Of River Covered By Plant

In recent years, people began to concern with the hydraulic characteristics of river covered with plant gradually. Because when the riverbeds are covered with plant, adverse effect will be produced to the river. This paper will be based on the situation of flow of the entrance of HuaiHe-to-Yangze river (JinHu section) and focused on effect of plant resistance to water flow, which is studied experimentally and theoretically in physical model.Based on the achievement of previous research results of roughness and formula, a new expression for calculating roughness is deduced. Study different hydraulic characteristics, such as reed density, coverage, hydraulic radius, how to affect roughness. The main researches as follows:1、According to the model design theory, in order to guarantee the resistance model zone, the model should meet the requirements of the water depth. Simultaneously, our school hydraulic test hall site area, and test main purpose:measurement of each flow corresponding canal water surface lines long, will be taken into consideration. With all the above factors, researcher will use distorted model which has a different than feet the vertical and horizontal. Use fixed bed flow model. Meet the gravity similar and resistance similar conditions.2、 According to theoretical analysis of the river resistance, based on the achievement of previous research results of roughness and formula, a new expression for calculating roughness is deduced.(1)No-submerged vegetation comprehensive roughness formula the comprehensive roughness n varies directly as the square root of plantdensity(?) ApH, The water the square root of vegetation coverage (?) and Hydraulic radius of2/3square R3, The bottom slope I has no impact on it.(2)Submerged vegetation comprehensive roughness formula Its form is similar with no-submerged vegetation. the Comprehensive roughness n varies directly as the square root of vegetation density (?) ApH The water the square root of vegetation coverage (?) and Hydraulic radius of2/3square R(?), The bottom slope I has no impact on it. But there is also a difference. Under the same conditions, submerged plant comprehensive roughness formula is smaller than no-submerged vegetation condition.(3) we mainly study the influence of resistance:Water depth increases, roughness decrease, Coverage of reed increase, roughness decrease...