Author(s): S. Benmamar; A. Kettab; C. Thirriot
Linked Author(s):
Keywords: Boundary layer; Stepped channel; Free surface
Abstract: From the crest of a chute or from an upstream gate, a bottom turbulent boundary layer develops. We present a numerical model of the two dimensional flow boundary layer in stepped channels with steep slope, which is based on the implicit finite difference scheme. From the mass and linear momentum conservation equation taking into account characters of the boundary layer, a system of non linear parabolic equations governing the flow has been developed. The turbulence stresses are closed by using k-ε model. A discrete system of equations has been obtained, allowing to calculate the velocity profile, water surface profiles, the boundary layer thickness and position of inception of air entrainment. The latter has been determined as intersection of the boundary layer and the free surface. A numerical model is presented to analyse the location of the start of air entrainment and the variables of the flow (velocity, turbulent kinetic energy, turbulent kinetic energy dissipation and turbulent viscosity).
Year: 2003