三维非定常水下超空泡射弹大涡模拟研究

Large Eddy Simulation of Three-Dimensional Unsteady Flow Around Underwater Supercavitating Projectile

基于N-S方程及PISO算法,考虑气液间相变,采用大涡模拟湍流模型和VOF方法,对绕三维水下超空泡射弹的非定常空泡流动进行了数值模拟.通过计算结果得到了超空泡的形成过程.计算了不同攻角条件下的超空泡形态,给出了射弹表面的空泡厚度分布曲线.计算了不同空化数条件下的超空泡无量纲长度和厚度,计算结果与实验数据吻合较好.计算结果表明:当空化器直径一定时,超空泡特征长度与特征直径随空化数的增加而减小;射弹航行攻角对超空泡形态影响较大,其显著地改变超空泡形态的轴对称性.

Based on the N-S equations and algorithm pressure implicit split operator（PISO） ,three- dimension unsteady cavitating flow around supercavitating projectile was numerically simulated by adopting the large eddy simulation （LES） turbulence model and volume of fluid （VOF） method,and the mass transfer between gas and liquid was considered. The forming process of su- percavity was achieved. On this basis, the cavity configuration was calculated at different attack angles, and the distribution curves of cavity thickness on the surface of projectile were also given. The dimensionless length and thickness of supercavity under different cavitation numbers were calculated. The calculation result is consistent with experiment result. The calculation results indicate that when diameter of cavitator keeps steady, the characteristic length and diameter decrease with the increase of cavitation number. The attack angle affects supercavitating shape greatly,which evidently changes axis-symmetry of supercavitation.