Large eddy simulation study of cavitating flow dynamics on a small-amplitude oscillating blade

Unsteady cavitating flow dynamics over oscillating blades have attracted increasing attention in recent years. To elucidate cavitation instabilities induced by small-amplitude blade oscillations, this study employs large eddy simulation to investigate cavitation behavior over both stationary and oscillating blades. For the stationary configuration, the numerical results reasonably reproduce the experimentally observed transition from non-cavitating flow to attached cavitation and unsteady cloud cavitation with increasing angle of attack. For the oscillating configuration, the largest cavitation cloud appears during the transition from the maximum angle toward the mean angle due to hysteresis effects. Cavity destabilization is associated with the upstream propagation of a condensation shock inside the attached cavity. The oscillatory motion also modifies the distribution of total resolved fluctuation energy and the directional organization of the resolved fluctuation covariance within the investigated mid-span region. These results indicate that small-amplitude blade oscillations can substantially affect unsteady cavitation dynamics and resolved unsteady-flow organization.