中文摘要：

研制进行高速物体出水实验的实验设备。阐述水下高速物体出水时,物体、超空泡和尾迹与自由液面相互作用的实验研究结果。试验整个物体在水下高速运行直到完全出水的过程;演示空泡在水下形成及在自由液面附近溃灭的过程,并采用高速摄影仪记录下来。通过照片和数据分析,结果表明：当物体运动速度达到40 m/s左右,是从空化气泡发展成超空泡的临界速度;当速度小于40 m/s时,会出现局部空化,并且速度减弱时呈现振荡趋势;大于此速度,速度减弱时则呈线性;物尖露出水面前一刻的瞬时速度为出水前的谷底值;物体完全出水时,在自由面附近形成了有向上运动趋势的气液混合现象。

英文摘要：

This paper describes a study on the interaction of supercavitation and free surface when underwater high-speed blunt body exits from the water surface.A slender metal nail is shot into a water tank from its bottom.The nail moves upwards as an underwater high-speed moving body until it completely leaves the water surface and enters the above air space.The experiment demonstrates the formation of cavitation in the water and near the free surface as well as the collapse of the bubbles.The flow field is visualized by using a high-speed camera.The experimental results indicate that the speed of 40 m/s is the critical speed from which cavitation transits into supercavitation.When the speed is less than 40 m/s,partial cavitation on the slender body appears.The body speed exhibits an oscillatorily decreasing trend.Above the critical speed,the body speed decreases linearly.The instantaneous velocity of the nail tip just exiting water free surface is the lowest.There is a gas-liquid mixture phenomenon near the free surface when the nail body leaves the water surface completely.