Thin-Shear-Layer Model in Supercritical Hydraulic Flow

Abstract

A supercritical, free-surface flow on an adverse incline has been modeled as a “thin-shear-layer” with algebraic eddy-viscosity included to account for turbulent shear stresses. The model has been solved numerically by a finite-difference technique for parabolic systems. Turbulent-viscous and adverse gravity effects are found to interact via the free-surface behavior in a way that leads to breakdown of the steady two-dimensional flow. Computed breakdown positions, velocity, and flow depth developments are compared with experimental and semi-empirical hydraulic results.