Vortex dynamic analysis of unsteady cavitating flows around a hydrofoil

Unsteady cavitating flows around a hydrofoil are calculated. Vortex dynamics are used to analyze the flow structure. Local swirling correction turbulence model is adopted to close the governing equations. Validation of the LSC turbulence model can be reached comparing with experimental results. Vorticity transport equations are conducted to analyze the influence of cavitation on vorticity transport process. The results show that: The LSC turbulence model can reflect the influence of the local swirling on cavitating flows well. It can get a good compromise with experimental results. Unsteady cavitation process contains developing of complex vortex structures. Re-entrant jet near trailing of attached cavity leads to distinct changes of velocity gradient, which has great influence on production and dissipation of vorticity. Intensive mass transfer between liquid and vapor phase may induce the volumetric expansion or contraction and baroclinic torque. Two factors mentioned above keep changing and result in unsteady distributions of vorticity. Cavitation may lead to unsteady mass and momentum transfers between liquid and vapor phase, which will change turbulence and vorticity distributions distinctly.