2024 Volume 80 Issue 16 Article ID: 23-16078
In mountain rivers, we often see three-dimensional vortex motion caused by large rocks and boulders. To solve these flow, a non-hydrostatic quasi-three dimensional model considering flow equations on boundary surfaces is used. But, there are issues with analysis accuracy. So, we focused on its characteristic evaluation method of vertical velocity distribution by cubic function, not considering boundary condition near the riverbed. To improve this problem, we divided the computational area into two layers, and added the additional boundary conditions. The purpose of this model improvement is to solve complex flow in the vicinity of the riverbed more acuurately. At the same time, we noted the inflection point and set as the boundary surface corresponding to the maximum position of the Reynolds stress distribution. We determined the outline of this new model using the three dimensional open-channel flow with rough bed. As a result, it was able to evaluate backwater regions and complex secondary flow.
