Two-dimensional free surface flow numerical model for vertical slot fishways

Abstract

Numerical results of a vertical slot fishway study are presented. The Saint-Venant equations are solved using TELEMAC-2D. Turbulence modelling uses the classical two equations k-epsilon closure model. A comparison with velocity measurements performed at the Laboratoire d'Etudes Aerodynamiques of University of Poitiers, France, using particle image velocimetry and acoustic Doppler velocimetry permitted to validate numerical results. Turbulence modelling is required not only to have a fish-friendly flow but, more remarkably, by the fact that taking a constant eddy viscosity model gives incorrect mean flow patterns. Three longitudinal slopes were tested. The validity of the k-epsilon closure model is discussed. Special attention was paid to the calculated turbulent kinetic energy and the energy dissipation rate. This last parameter is of great interest because its spatial distribution significantly affects the progress relative to fish passage efficiency.