Numerical Simulation of Cavitation and Hydrodynamic Characteristics of Supercavitating Projectile in Shear Flow

Abstract

In order to study the cavitation and hydrodynamic characteristics of supercavitating projectile in shear flow,the Mixture multiphase model,Schnerr-Sauer cavitation model and Realizable k-ε turbulence model were used to simulate the underwater supercavitating projectile in shear flow. The inflow average velocity was 600 m/ s,and the shear rates range from 0 to 7 500 s-1. In the uniform flow,the supercavity surrounding the projectile is symmetrical. The drag is dominated by pressure drag,and the lift coefficient is 0. In the shear flow,the supercavity is asymmetric and deviates towards the low-speed side. Besides,the pressure drag increases slightly,leading to the increment of the drag coefficient. Because the flow around the high-speed side is faster,the vortex at the low-speed side produces a more significant entrainment effect,which makes the projectile suffer from the normal viscous force orientating towards the low-speed side,and the lift coefficient becomes negative. When the shear rate increases further,the shoulder on the high-speed side contacts the water. The viscosity around the projectile increases,resulting in a significant increase in the drag coefficient. The water pressure is substantially greater than the saturated steam pressure,and the normal component of pressure acts more strongly towards the low-speed side,resulting in the further decrement of the lift coefficient.