Field Measurements and Flow Modeling of Overbank Flows in River Severn, U.K.

Abstract

Field measurements of velocity and turbulence have been carried out in a study reach of the River Severn (U.K.) during overbank flows. Directional current (DCM) and acoustic Doppler Velocity (ADV) meters have been used for the field measurements of velocity and turbulence particularly in the interface region between main channel and floodplain. The values of local shear velocity and roughness length for the reach under study were calculated using measured velocity data. The distributions of turbulent intensities, and the Reynolds stresses are also presented. A two-dimensional depth averaged numerical model is used to investigate how accurately the field measurements are reproduced. A fully 3D model of the river reach is also constructed using CFX and the results are presented.

Keywords: Velocity, turbulence, field measurements, overbankflow, flow modeling