超空泡航行体尾拍参数对水动力影响的数值研究

Numerical Study on Hydrodynamic Influence of Tail-slap Parameters of Supercavitating Vehicles

摘要:

航行体跨介质高速入水后通常会形成入水空泡，入水空泡与航行体的耦合作用产生的水动力对入水后的运动具有重要影响。而航行体尾部在空泡内往复拍击运动的作用力是影响航行体水下运动的关键因素之一。在尽可能减少运动与空泡耦合作用干扰的条件下，通过不同航行体尾部拍击频率与摆动幅值的数值模拟，获得了指定运动规律下的空泡和尾部水动力特性变化规律，可为深入理解尾拍过程水动力变化机制提供参考。研究结果表明，在本文研究范围内，当尾拍频率较小（f=5 Hz）时，尾拍法向力受航行体攻角（尾部浸没角）影响更大；当尾拍频率较大（f=100 Hz）时，尾拍法向力受航行体尾拍角速度的影响更大；在指定运动规律下，尾拍法向水动力峰值与尾拍幅值呈线性关系。

Abstract:

When underwater vehicles crosse the medium and enter water at high speed，an entry cavity is usually formed. The hydrodynamic force generated by the coupling interaction between the entry cavity and the vehicle has an important influence on vehicle motion after water entry. The force resulting from the reciprocating flapping motion of the vehicle tail inside the cavity is one of the key factors affecting the underwater motion of the vehicle. In this paper，under the condition of minimizing the coupling interaction between the motion and the cavity， numerical simulations with different tail flapping frequencies and swinging amplitudes of the vehicle are carried out to obtain the variation law of the cavity and the tail hydrodynamic characteristics under the specified motion law. This can provide a reference for deeper understanding of the hydrodynamic changes during the tail-slap process. The results indicate that within the scope of this study，when the tail-slap frequency is low（f=5 Hz），the tail-slap normal force is more significantly influenced by the vehicle’s angle of attack（tail submersion angle）. When the tail-slap frequency is high（f=100 Hz），the tail-slap normal force is more significantly influenced by the angular velocity of the vehicle. Under the specified motion law，the peak of the tail flapping normal hydrodynamic force is linearly related to the flapping amplitude.