细长体倾斜入水时的非平衡态超空泡气液两相流研究

采用高速摄影技术观察高速细长体倾斜入水后超空泡气液两相流形态发展变化过程并对其结果进行研究。分析48mm长的细长体在50m／s左右的入水速度工况下，分别以几种不同入射角度进入水中后相关的流体动力学特性过程。实验结果表明，当细长体倾斜入水时，其与水自由面接触产生的力矩改变了细长体的初始运动方向，使其偏转并产生有多重褶皱的非规则空泡体，细长体尾部也更容易在入水时与产生的空泡边界接触而打断超空泡，致使部分超空泡留在近自由面处。根据速度拟合曲线，验证了细长体倾斜入水情况下依旧有超空泡减阻作用。

The Non-Equilibrium Gas-Liquid Two-Phase Flow and Supercavitation Phenomenon during Water Entry of a Slender Body

The phenomenon of supercavitation during water entry of a high speed slender body has been studied experimentally with high-speed photography, and the results are studied deeply. The fluid dynamic processes of water entry of the 48mm long slender body at the speed of about 50 m/s in different incident angles have been analyzed specifically. Experimental results show that when the slender body tilt into the water in some incident angle, the contact with the free surface changes the torque generated by the initial movement direction of the slender body, which makes the slender body deflect and produce multiple irregular folds of the cavity. At the same time, the slender body breaks the supercavity more easily during water entry because of the interaction between the supercavity wall and the slender body, resulting in some supercavitation stays near the free surface. According to the curve based on the speed, it is verified that there is still a super-bubble drag reduction effect during water entry of a slender body.