Experimental study of ventilated supercavitating flows around a hemisphere cylinder

To understand ventilated supercavitating flows around a hemisphere cylinder, the unsteady process of development of ventilated supercavity and the flow field of wake around a hemisphere cylinder are observed by means of a digital particle image velocimetry system and a high speed video camera. The results show that a steady transparent air area is observed near the foreside of the ventilated supercavity in the process of development of ventilated supercavity, and there is a vortex in the rear of supercavity. Water and air mixed area is full of the rear part, and finally bubble shedding in large scale appears, which has great effect on the flow field at the rear of a hemisphere cylinder. Compared to no-ventilated conditions, the range of low velocity area in the wake obviously expands, and the velocities of measuring points in various profiles decrease. The upper and lower velocimetry ropes stretch backward and enlarge by degrees as the ventilated cavity region extends rearward, becoming many dispersed velocimetry groups that gradually dissipate downstream.