Compressibility characteristics of transient sheet/cloud cavitation – a numerical survey

In this study, the transient compressible sheet/cloud cavitation around the stationary blade is investigated using a Computational Fluid Dynamics (CFD) method. The instantaneous characteristics of the cavity, such as the destabilization of the sheet cavity, the transformation of the sheet topology into the cloud topology, and the process of shrinking and collapsing of the cloud cavity, are reasonably replicated. The examination of the sheet cavity reveals that the disturbance moving upwards within the cavity is a condensation shock. This shock adheres to the classical Rankine–Hugoniot jump conditions and travels at a hypersonic speed. Once the condensation shock reaches the point where the cavity separates, the sheet cavity unlocks from the surface and transitions into a cloud cavity. The cloud cavity undergoes a reduction in size as it is carried downstream and collapses in the zone of high pressure. Investigations of a small cloud cavity reveal that its collapse results in the release of immense pressure, reaching several million Pascals. Furthermore, the relationship among potential energy, kinetic energy, and pressure wave energy during the collapse of the cavity is exposed, contributing to a more comprehensive comprehension of this intricate phenomenon.