Effect of Cavitation on Vortex Dynamics in a Submerged Jet

Abstract

The effects of cavitation on vortex dynamics in a submerged planar laminar forced jet were studied numerically. A locally homogeneous cavitation model that accounts for nonlinear bubble dynamics and bubble/bubble interactions within spherical bubble clusters was employed. The effects of varying key flow and cavitation model parameters on flow-cavitati on interactions were investigated. The parameters varied include the cavitation number (vapor pressure), the bubble number density, the bubble-cluster radius, and the Reynolds number. The results showed cavitation occurring in the cores of primary vortical structures when the local pressure fell below the vapor pressure. Low levels of void fraction caused significant vortex distortion, with the details depending on the model parameters. For higher Reynolds numbers and small values of the bubble cluster radius, cavitation inhibited vortex pairing and resulted in vortex splitting. All of the above observations were in good qualitative agreement with previous experimental and numerical studies. The vorticity transport equation was used to examine the mechanisms behind the effects of cavitation on the vortex structures and it was found that both the dilatation and baroclinic torque terms played a role.