Abstract
A practical numerical bed variation method is required for evaluating various functions of groins installed in rivers. The conventional depth integrated (2D) computation method, which has been used for practical computations of flood flows and bed variations in rivers, is inadequate for local scouring around hydraulic structures due to 3D flow. However, the use of full 3D turbulence flow computation methods is not common for floods in rivers. Therefore, a refined depth integrated model is required for the practical use. In this paper, the Bottom Velocity Computation (BVC) method is proposed to evaluate velocity acting on sediment particles effectively and compute bed variation in a channel. In the BVC method, depth-integrated horizontal vorticity and water surface velocity equations are computed simultaneously with shallow water equations and a depth averaged turbulence energy transport equation. To compute bed variation around submerged groins, evaluation methods for non-equilibrium bed load and bed tractive force by using bottom velocity is presented. The applicability of the method is discusse d through the comparisons with the laboratory experimental results of flows and bed variations in a channel with submerged groins.
