航行体沾湿区域对空泡尾流结构的影响

In order to study the influence of wetted area of vehicle on the wake structure of ventilated supercavity, the CFD method was used to simulate the unsteady variations of the wetted area and the vorticity in the wake of a supercavitating vehicle in the process of changing the angle of attack. The transformation mechanisms of different flow structures in the wake of a cavity are revealed by analyzing the changes of pressure and vorticity in the wake flow field. The results show that, under the low Froude number, a high pressure zone exists above and below a twin-vortex tube at the tail of cavity. Due to the influence of environmental pressure difference, the pressure below the tube is higher than that above it. The flow direction between the two vortices is upward to form a pair of twin vortices rolled up in the center. With the increase in the angle of attack of vehicle, the wetted area causes the cavity to form the wake structure of three-vortex tube. The pressure in the high pressure area below the vortex tube is lower than that above it, and the flow direction between the two vortices below the cavity is downward to form a pair of twin vortices rolled down in the center. During the transition from the twin-vortex tube to the three-vortex tube, the pressures and velocities of the upper and lower parts of cavity wake change alternately, thus forming the wake structure of four-vortex tube.