Numerical simulation of asymmetric flow in a vertically downward intake

This paper describes the results of a numerical simulation on a vertically downward intake. A three dimensional numerical model is developed that solves Reynolds Average Navier Stocks and turbulence closure equations. A pressurized algorithm couples continuity and momentum equations and models the free surface drop. Both free surface and sub surface vortices are identified and their strength and locations estimated. Results show that in this specific geometry free surface vortices are stronger than subsurface ones, which may also be ingested into the pipe, due to unsteady conditions. The acceleration length for vertical velocity component close to the pipe is about twice pipe side, which is in close agreement with predicted results for axial component in horizontal intakes.