圆柱体垂直入水空泡形态试验

Vertical water entry cavity of cylinder body

在不同攻角和不同速度条件下,对圆柱形运动体垂直入水空泡形态进行试验研究.对140°锥角头型圆柱体在零攻角和带攻角条件下进行垂直入水试验,分析了低速垂直入水所引起的入水空泡生成、发展和闭合流动过程以及空泡稳定性等;利用平头圆柱体进行不同速度条件下垂直入水试验,分析了入水速度对空泡闭合方式和形态的影响.研究结果表明:在试验速度范围内均能形成稳定的入水空泡,并经历生成、充分发展、空泡闭合以及最后完全脱落的过程,不同发展阶段具有不同的稳定性,其闭合方式和形态与入水速度密切相关.

Experimental studies of the vertical water-entry of cylinder bodies were conducted using high speed camera to capture the splashes over the water surface and the subsurface cavity shapes. The cavities for mation and stability were discussed for 140°conical cylinder bodies fall into water freely. Experiment results show that the air cavity formed at very low entry speed, and lots of complicated flowing phenomena accompa nied with the whole process of the formation, including splashes, cavity expand and cavity pinch-off. And the effects on the stability of the cavity due to the impact of tail were also discussed with vertical entry of the 140° conical cylinder at an angle of attack, and the results reveal that the impacts on the cavity play different roles for stability of cavity at different stage of the whole process of formation. Finally, the effects on the cavity shapes and the pinch-off of vertical water-entry of right cylinder were conducted at various entry speeds. It shows that tbe cavity shapes and type of pinch-off are great depended on entry speed.