Large Eddy Simulation of the cavitating flow around a Clark-Y mini cascade with an insight on the cavitation-vortex interaction

Abstract

In this research, the Large Eddy Simulation method is utilized to predict the cavitation-vortex interaction in the flow around a Clark-Y mini cascade along with the dynamical processes of the U-type cavity, analyzed using the Lamb vector divergence transportation. To provide a novel perception of the development of the U-type cavity, various fundamental mechanisms of the periodic evolution of the U-type cavity are investigated thoroughly. The dynamical progress explicates the mechanisms that generate the high-pressure zone and low-velocity zone. This mechanism, combined with the re-entrant jet and vortex motions plays a significant role in the development of the U-type cavity. Since the Lamb vector curl associates the vorticity transport equation and is closely related to the source of vorticity of the vortex evolution, the Lamb vector curl captures the vortical structures which show good agreement with the Ω-method results. In addition, the distributions of high- and low-momentum flow in the wake of the cascade are delineated by the Lamb vector divergence. The transition from the maximum to the minimum of the lamb vector divergence in a region illustrates a quasi-cyclic behavior that is closely related to the momentum transport mechanisms and the cyclical motions of the vortex.