航空学报 > 2023, Vol. 44 Issue (21): 528488-528488   doi: 10.7527/S1000-6893.2023.28488

受约束航行体跨介质试验方案设计及其CFD分析

刘君遥, 于勇()   

  1. 北京理工大学 宇航学院,北京 100081
  • 收稿日期:2023-01-29 修回日期:2023-04-06 接受日期:2023-05-29 出版日期:2023-09-22 发布日期:2023-09-22
  • 通讯作者: 于勇 E-mail:yuyong@bit.edu.cn
  • 基金资助:
    省部级项目

Experimental scheme design of constrained vehicle in a trans-media process and CFD analysis of scheme

Junyao LIU, Yong YU()   

  1. School of Aerospace Engineering,Beijing Institute of Technology,Beijing 100081,China
  • Received:2023-01-29 Revised:2023-04-06 Accepted:2023-05-29 Online:2023-09-22 Published:2023-09-22
  • Contact: Yong YU E-mail:yuyong@bit.edu.cn
  • Supported by:
    Provincial or Ministerial Level Project

摘要:

航行体在跨水空介质过程中因受到空气、水等多相流场的作用,其所受到的力载荷和表面压力呈高度非线性和时变性特征。针对该载荷特性和跨介质过程中多相界面演化,设计了航行体入水-出水完整运动过程中,其所受流体力载荷测量及水空界面演变可视化拍摄方案。为对试验方案做前期验证,采用流体体积法(VOF)多相界面捕捉模型,并在重叠网格框架下对航行体旋转跨水空介质过程进行了三维流动模拟。分析了航行体在不同旋转入水速度、不同最大入水深度下完成跨介质过程所受到的流体力载荷特性、相界面演化、压力场、速度及涡量演化特征。数值结果表明:相比于另外两方向,迎水运动方向所受力载荷呈主导作用,其数值变化随入水深度呈准轴对称分布,并随旋转入水速度增大而增加。不同最大入水深度下,航行体表面及沿运动方向中截面压力场表明,高压区始终存在于航行体前缘头部,低压区则分布于肩部区域,且其峰值受最大入水深度影响有限。流线的分布则说明了航行体跨介质过程中复杂的流动特性,其速度峰值存在于航行体尾部不稳定流动区域。跨介质过程中,涡结构会因运动状态改变和水空不同介质作用而产生分化、生长、耗散和范围延伸。此外,较小的最大入水深度会产生更加复杂的流场分布、涡结构尺度以及涡量发展特性。

关键词: 跨介质流动, 力载荷, 多相界面, 重叠网格, 涡量分析

Abstract:

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.

Key words: trans-media flow, force load, multiphase interface, overset mesh, vorticity analysis

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