Two dimensional analytical solution for a compound open channel flow with submerged vegetation

• 1、State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University,Wuhan 430072

Abstract：This article builds a two dimensional solution for a compound open channel with the influence of submerged vegetation. Our goal is giving a method to describe the transverse distribution of the depth-averaged velocity in the lengthways direction. Firstly, by analyzing previous theories about the mixing layer, we combine the previous method and divide the cross-section into four regions: steady main region; mixing main region; mixing vegetated region and steady vegetated region. Then, according to previous research, we propose a definition of velocity scale in the vegetated region (including mixing vegetated region and steady vegetated region). By applying the velocity scale, we simplified the depth-averaged N-S formula. Using the boundary conditions and secondary flow theories used by previous investigators, we finally get the solution of the depth-averaged N-S formula. At the same time, we carry out an experiment in the State Key Laboratory of Water Resources and Hydropower Engineering Science in Wuhan University, Wuhan, China. At last, we apply the model into the experiment data in this research and that of Professor Yang Kejun, whose experiment was conducted in State Key Laboratory of Hydraulics and Mountain River Engineering in Sichuan University, Sichuan, China, and get good results.

Keywords： submerged vegetation compound section channel two dimensional model depth-averaged velocity distribution in the crosswise direction