Transition and gas leakage mechanisms of ventilated cavities around a conical axisymmetric body

Abstract

Experiments are performed on gas entrainment and leakage mechanisms of various ventilated cavity flow patterns around a conical axisymmetric body. As the ventilation rate increases, the size of shedding foam grows while the shedding frequency reduces, leading to balanced gas injection and leakage. The mechanism controlling cavity hysteresis is quantitatively explained using a validated gas leakage model in which the foam is periodically shed as a vortex ring. The closure discrepancy between fully developed cavities (recirculating vortex) and free-standing supercavities (continuous vortex tube) is explained by the adverse pressure gradient difference in the cavity streamwise direction.