THREE DIMENSIONAL NUMERICAL ANALYSIS OF OPEN CHANNEL FLOW WITH RIGHT-ANGLED CONFLUENCE BY LARGE EDDY SIMULATION

Abstract

 Three dimensional and unsteady flow structures generated at a river confluence are still not fully understood. In the present study, a fully-resolved LES (Large Eddy Simulation) with a VOF (Volume of Fluid) method capable of treating free surface boundary was performed to investigate three dimensional structures of turbulent flow and water surface variations at a right-angled confluence. The averaged flow structures and water surface variations obtained by the LES were compared with detailed measurement data obtained by PIV. As a result, it was shown that the LES was able to predict a size of a recirculation region in the streamwise direction and a width of that in the spanwise direction. Moreover, the LES was also able to predict that the width of the recirculation region varies in the depthwise direction in a complicated manner.