Mechanisms of cavitation–vortex interactions and non-monotonic shedding behind a wedge-shaped body

The complex coupling between cavitation and vortex dynamics in the wake of bluff bodies influences hydrodynamic performance and structural integrity. This study employs a shear stress transport delayed detached eddy simulation framework to investigate turbulent cavitating flow over a wedge-shaped body. The simulations capture the experimentally observed non-monotonic trend of the vortex-shedding frequency, which peaks at σ = 1.8. A quantitative budget of the relative vorticity transport equation elucidates the underlying mechanisms: during the frequency-increase phase (incipient to partial cavitation), baroclinic torque localized at the liquid–vapor interface accelerates the initial vortex roll-up. Concurrently, the moderate cavity preserves spanwise coherence by suppressing three-dimensional breakdown. In contrast, the transition to fully developed cloud cavitation is primarily driven by vortex dilatation arising from rapid volumetric expansion and compression. This dilatation interacts with coherent spanwise rollers, fragmenting them into smaller-scale structures, thereby contributing to the reduction of the shedding frequency. A comparative boundary analysis further decouples the geometric blockage effect induced by lateral walls from intrinsic cavitation dynamics. The results indicate that the complex wake dynamics arise from the superposition of intrinsic cavitation modulation and extrinsic geometric blockage.