Study on high-speed water entry process of non-rotating vehicles

非回转体航行器高速斜入水过程研究

School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China

Received: 9 September 2022

Abstract

The non-rotating trans-media vehicle can better adapt to the hypersonic flight conditions, but new problems in the hydrodynamic characteristics and motion stability arise during the water entry process. With the VOF multiphase model, Realizable k-ε turbulence model, and Schnerr-Sauer cavitation model, this paper establishes a simulation method of coupling the movement of non-roating body into water with multiphase flow fields based on overset grid technology, and the accuracy of the established model is verified. The simulation calculation of the oblique water entry process of the vehicle with different ratio of short axis to long axis in cross section is carried out. And the results show that although the ratio of short axis to long axis in cross section does not change the cavitation morphology, it affects the hydrodynamic and kinematic characteristics of the vehicle by influencing the relative position of the cavitation. As the ratio of short axis to long axis decreases, the motion stability of the vehicle increases gradually. However, if the ratio of short axis to long axis is too small, the drag reduction effect will be weakened, and the structure will suffer a bigger load.

摘要

非回转体跨介质航行器能够更好适应空中高超声速飞行工况, 但是在入水过程中的流体动力特性及运动稳定性存在新的问题。采用VOF多相流模型、Realizable k-ε湍流模型、Schnerr-Sauer空化模型, 结合重叠网格技术, 建立了非回转体入水过程运动与多相流场耦合的仿真方法, 验证了所建模型的准确性, 对横截面短长轴之比不同的航行器开展了斜入水过程仿真计算。结果表明: 横截面短长轴之比虽然不会改变空泡形态, 但是通过影响泡体相对位置关系对航行器的流体动力特性和运动特性都有影响; 随着短长轴之比的减小, 航行器的运动稳定性逐渐增加; 但短长轴之比过小, 则会影响减阻效果, 并对结构安全性不利。