受约束航行体跨介质试验方案设计及其 CFD 分析

The force load exerted on the vehicle and the surface pressure exhibit an essential nonlinear behaviour and a time-varying characteristic due to the complicated multiphase flow in the process as the vehicle crosses the water-air interface. Considering the load feature and the multiphase interface evolution,a visualization experiment for force load measurement and multiphase interface evolution is designed. To verify the experiment scheme,a numerical framework is established by adopting the Volume of Fluid(VOF)multiphase model coupled with the overset mesh. The force load,changed phase interface,pressure,velocity and vortex structure evolution of the vehicle at different maximum depths of water entry and water entry rotation speeds are simulated. The simulation results indicate that the force load in the upstream face plays a main role compared with that in the other two directions,and its evolution shows a quasi-axisymmetric characteristic with the depth of water entry. In addition,the increased rotation speed enhances the force load exerted on the vehicle. The high-pressure region always exists on the head of vehicle and the low-pressure region is distributed on the shoulder. The influence of maximum depth of water entry on the pressure peak is limited. The distribution of streamline illustrates the complexity of the trans-media flow,and the velocity peak exists in the tail of vehicle. The vortex structure generates differentiation,growth,dissipation and extension due to the changed motion state and the action of different fluid in the trans-media process. Besides,the decreased maximum depth of water entry results in more complex multiphase interface,vortex structure scale and vortex evolution characteristics.