Computational fluid dynamics modelling of flow and energy fluxes for a natural fluvial dead zone

Abstract

This study links together information that characterizes the energy and momentum fluxes across the shear zone between the main flow and a dead zone in the UK on the River Severn [1-3]. The depth-averaged flow in and around the dead zone is modelled using TELEMAC-2D, with semi-distributed eddy viscosity and bed roughness, and compares well with some distributed field measurements within the reach. The resulting velocity field is then used to provide momentum fluxes for a finite difference model incorporating finite volumes (FDFV model) numerical scheme that has been developed to solve depth averaged advection-diffusion of thermal energy in a body fitted co-ordinate system. Assuming that buoyancy forces can be neglected, the gross hydraulics of the system explains much of the temperature distribution that was observed using infra-red aerial imagery.