Numerical Simulation of Three-Dimensional Flow in a Patchy Vegetated Compound Channel

Abstract

Riparian vegetation grows excessively in floodplain areas of natural rivers and canals which affects the conveyance capacity of the channel and alters the flow velocity. Therefore, it is necessary to understand the impact of floodplain vegetation on flow dynamics in a trapezoidal compound channel. Therefore, the main focus of this study is to develop a three-dimensional (3-D) numerical model to investigate the flow dynamics in a floodplain vegetated compound channel. ANSYS FLUENT software was employed to conduct the numerical simulations, and Reynold’s Stress Model (RSM) was chosen to accurately estimate turbulence parameters during simulations. The numerical simulation data were validated using previously published data. The cross-sectional flow characteristics revealed a significant reduction in flow velocity within the floodplain region due to the high resistance offered by the vegetation. Additionally, turbulence intensity was also reduced in the vegetation region. As the flow velocity and turbulence decrease within the floodplain-vegetated trapezoidal compound channel, favorable conditions for sedimentation are created which are suitable for flood mitigation and the growth of aquatic ecosystems.