Numerical investigation of cavitation vortex dynamics in unsteady cavitating flow with shock wave propagation

The objective of this paper is to study the cavitation vortex dynamics in compressible turbulent cavitating flow, around a NACA66 hydrofoil. The simulations are conducted based on the open source software OpenFOAM, solving the compressible governing equations together with the Tait state equation for water and ideal gas state equation for vapor. The Saito cavitation model is used to model the cavitation phase change process and SAS SST turbulence model is adopted to account for the turbulence effects. The numerical results showed a good agreement with the experiments. The cavity evolution presents quasi-periodic behaviors, and the alternative re-entrant flow movement and shock wave dynamics play an important role in cavitation vortex dynamics. Strong coherent relationship between cavitation behaviors and vortex dynamics is illustrated. Based on the budget analysis of vorticity transport equation, it shows that during the attached cavity growth, the re-entrant flow development and the cloud cavity being shed stages, the baroclinic torque term dominates the vorticity transport process. During the shock wave propagation stage, the vortex dilatation term dominates in the attached cavity sheet region. Besides, the baroclinic torque term has strong influence on vorticity transport characteristics.