Numerical investigation of cloud cavitation and cavitation noise on a hydrofoil section

Abstract

Partial cavitating flow and cloud cavitation on a hydrofoil section are numerically investigated. A fully compressible, density based homogeneous equilibrium model is employed along with a RANS turbulence model and high-order numerical methods based on a sixthorder central compact scheme and localized artificial diffusivity scheme are used to resolve the cavitating flow and pressure waves generated by cloud cavitation. Predicted results compare well with the experimental measurements for steady/unsteady partial cavitating flows on a NACA66 hydrofoil at cavitation number, ?=1.0-1.4 and angle of attack 6 and 8 degree. Detailed experimental data from the work of Leroux et al. were provided by Prof. J.-A. Astolfi at Institut de Recherche de l Ecole Navale, France. Numerical visualizations of cloud cavity evolution and surface pressure signals show relatively good agreement with the experimental data. The re-entrant jet flow and pressure wave generated by collapse of cloud cavity are closely investigated. The mechanism associated with two different unsteady dynamics of cloud cavitation observed in previous numerical/experimental study for angle of attack 6 and 8 degree are further explored using the present computational results. The pressure pulse generated by the collapse of bubble cloud and the flow-blockage effect caused by a large cavity cloud are found to be responsible for the shifting of cloud cavitation dynamics.