Investigation of Velocity Distribution in an Open Channel with Rigid Floating Vegetation Islands

Abstract

Floating Vegetation Islands (FVIs) are commonly found on the shallow surfaces of open channels, such as rivers and canals. These FVIs can significantly alter the flow characteristics, causing changes in flow velocity and turbulence around the canopy zone. This research employs Computational Fluid Dynamics (CFD) modeling to investigate the impact of FVIs on flow velocity in an open channel. The numerical simulations were conducted using ANSYS-FLUENT software, utilizing the Reynolds Stress Model (RSM). Three patches of FVIs with a density of 2.0583/cm2 were considered in the simulations. The findings demonstrate a substantial reduction in flow velocity, up to 100%, within the vegetation zone, while a velocity increase of 285% was observed in the free adjacent zone. A shedding behavior with large and turbulent wake structures was observed behind the floating patches, whereas a significant difference in the velocity magnitudes between the upper canopy part and the lower free part (water column) was observed. This study highlights the significant influence of FVIs on flow dynamics in open channels.