Physical and numerical study on the transition of gas leakage regime of ventilated cavitating flow

The objective of this paper is mainly to investigate the ventilated cavitating flow around an axisymmetric body with a focus on the gas leakage mechanisms via combining experimental and numerical methods. A high-speed camera technique is used to record the ventilated cavitating flow patterns. The numerical simulation is performed with a free surface model and Filter-based turbulence model (FBM). Good agreement can be obtained between the experimental and numerical results. In the formation of a ventilated cavity, there are three typical gas leakage types with different Froude numbers Fr and gas entrainment coefficients C-Q, including RJ closure mode with gas leakage of toroidal vortex shedding (TVS-RJ), TV closure mode with gas leakage of twin-vortex tube entrainment (TVTE-TV), and the coexistence of toroidal vortex shedding and twin-vortex tube entrainment (TVS-TVTE). The internal flow characteristics revealed three distinct regions with the ventilated cavity, including the ventilation influence region, the internal shear layer and the reverse flow region. With the increase of C-Q, the incline angle of the cavity bottom surface alpha gradually decreases. When the incline angle alpha decrease to a critical value of similar to 17.1 degrees, the flow separation disappears completely and the flow regime migrates completely to TV cavity from RJ cavity.

Automated summary

This paper investigates the ventilated cavitating flow around an axisymmetric body, focusing on the gas leakage mechanisms, and achieves good agreement between experimental and numerical results. Three typical gas leakage types are identified during the formation of a ventilated cavity, and the internal flow characteristics reveal three distinct regions.