通气超空泡内部流场的PIV实验图像处理

PIV image processing method of the ventilated super-cavitating flow

PIV测试是流体动力学实验研究的重要方法之一,可以成为通气超空泡内部流场结构实验研究的有效手段。通过水洞实验利用PIV对通气超空泡内部流场进行测试时,激光在气液两相界面处会发生折射,导致实验图像变形和失真。文章分析了激光在空化流场中各相界面的折射特性和PIV实验图像的变形规律;在此基础上,推导了图像变形的分析计算式,给出了通过原始流场图像获取真实流场图像的还原处理方法;编制了图像还原计算程序,并对原始PIV图像进行了处理,得到了反映真实空泡内部流场结构的图像。

Abstract：P IV is one of the most important measuring technologies in the hydrodynamics experiment, which has become an efficient way in the research on inner flow field of the ventilated super-cavitation. Refrac- tion would take place during the transmission on the liquid-vapor interface in the cavitating flow, which could cause the distortion of the experimental images. By analyzing the refraction of the laser between dif- ferent phases in the cavitating flow, an image processing method was carried out. In order to fix the distor- tion of the PIV original images, an images processing code was built. Images which represented the real structure of the ventilated super-cavitation were acquired by applying the processin~ code.