Comparison between the Analyses of Open Channel Flows with Rigid Vegetation Using a Detailed 2D Model and a Spatially-averaged Model

Abstract

Flow resistance is increased with vegetation and prediction of resistance is of great importance in river engineering. In this study, numerical simulation of open channel flows with rigid vegetation is carried out using a detailed two-dimensional depth averaged flow model with fine meshes and a spatially-averaged flow model with coarse meshes. Then, comparing the numerical results, the effects of the vortexes du e to shear instability and the vegetation density on flow structure is investigated. It is shown that the flow resistance due to vortexes can be reproduced by both a detailed two-dimensional model and a spatially-averaged model.