A study on the wake structure of the double vortex tubes in a ventilated supercavity

To study the wake structure of the double vortex tubes in a ventilated supercavity, the computational fluid dynamics (CFD) method based on the finite volume method and the volume of fluids (VOF) multiphase flow model were used to solve the Reynolds-averaged Navier-Stokes (RANS) equations for performing numerical simulation analysis on the wake structure of a supercavitating vehicle. By analyzing the reasons for the upward drift in the tail section of the supercavity and the formation of the double vortex tubes, the effects of gravity and the attack angle of the vehicle on the formation of gas leakage in the double vortex tubes of the supercavity were explained. The pressure and vorticity inside the vortex tubes were thereby analyzed as well. The results showed that, in addition to the gravitational condition, the wetted area of the vehicle with an attack angle also caused the supercavitating tail to form gas leakage in the form of double vortex tubes. Moreover, the wetted area played a dominant role compared to the role of gravity. The supercavity closure to the inside tail section was a high-pressure area, and this area separated downstream into two parts, resulting in the generation of the double vortex tubes. The vorticity and pressure in the vicinity of the vortex tubes attenuated downstream in the direction of the vortex tubes. When the tail section of the cavity leaked gas via three vortex tubes, the values of the vorticity inside the upper part of the vortex tubes became very small, and the air flow inside the upper part of the vortex tubes increased with the attack angle of the vehicle.