Effect of Cavitation on Vortex Dynamics in a Submerged Laminar Jet

Abstract

The effects of cavitation on vortex dynamics in a submerged, two-dimensional, 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 eow and cavitation model parameters on eow/cavitation interactions were investigated. The parameters varied include the cavitation number (vapor pressure), the bubble number density, the bubble cluster radius, and the Reynolds number.Theresultsshowedcavitation occurringinthecoresofprimaryvorticalstructureswhenthelocalpressure fell below the vapor pressure. Low levels of void fraction caused signiecant 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 preceding 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. Nomenclature b = buffer function D = nozzle diameter fv = void fraction h = half-width of the nozzle N = number of grid points n = bubble number density