垂直入水空泡内部压强分布数值研究(英文)

Numerical Simulation of Pressure Distribution in Vertical Water-entry Cavity

基于RANS方程,在VOF多相流模型中嵌入水蒸汽和水之间的质量输运模型成功实现了垂直入水空泡流的数值计算。通过与试验结果的对比说明了以上数值方法的可信性,并在此基础之上对带不同锥角头型圆柱体以不同速度垂直撞击自由液面后所生成的空泡内部压强分布进行了深入分析,结果表明:在入水空泡形成阶段,空泡内部压强会出现较大的降低现象,并随着空泡的发展压强值逐渐趋于稳定;空泡形成阶段空泡内部压强随入水物体头部锥角增加而增加;在开空泡阶段空泡内部压强低于环境压强,并随着入水速度增加而呈降低变化趋势,空泡内部压强轴向和径向分布较为稳定,没有较大的压强梯度;在空泡趋于闭合阶段空泡内部压强出现较大的波动,其变化规律与空泡内部空气复杂速度场变化规律相吻合。

Pressure distribution in vertical water-entry cavity is investigated computationally. Particular attention is given to the simulation method based on solving the time dependent Reynolds-averaged Navier-Stokes equations and the VOF （fractional volume of fluid） multiphase method with cavitation mass transfer model, and turbulence closure. Numerical results compared favorably with the experimental data show that the numerical method in this paper is able to capture the pressure evolution in the vertical water entry cavity properly. Pressure distributions in cavity are discussed for various entry speeds and nose shapes projectiles, numerical results show that the pressure drop in cavity is dependent on the entry velocity in open-cavity period, the pressure drop increases with the increment of entry velocity, In surface closure period, the pressure in the cavity presents complicated fluctuation features and the airflow velocity value increases too many times greater than the entry velocity.