Turbulent Structures in Gap Flow

Abstract

A computational study was carried out to investigate the effect of the gap between the body and the bed on the wake characteristics in shallow flows. A sharp-edged bluff body with two different clearances from the bed is employed in this investigation. The transient three-dimensional governing Navier-Stokes equations are numerically solved using a finite volume formulation with improved delayed detached-eddy simulation as a turbulence model. The volume of fluid approach is used in the current study as a free-surface modelling technique for locating and tracking the free surface. It is found that the existence and size of the gap influence the wake size and the location where the free surface is restored to its original and flat shape. This study also reveals that the fluid structures lose their symmetry about the center of the wake as the gap size increases.