全入射角度下平板冲击波的壁压载荷及局部空化特性

Characteristics of wall pressure and cavitation on the plate subjected to underwater explosion shockwaves at any angle of incidence

以平面波理论为基础,推导了无限平板在全入射角度下的冲击波壁压载荷计算公式,利用实验数据对壁压公式进行修正,提出了一种适用于计算有限尺度平板壁压的经验公式;分析了不同入射角度下壁压载荷的变化特性,初步研究了壁压载荷负压特性对平板局部空化的影响。结果表明:修正后的壁压曲线与实际壁压曲线吻合较好;入射角度的增大会加快壁压衰减过程,并使最低壁压的绝对值减小;随着药量或平板厚度的增加,壁压最低负压的绝对值增大,形成局部空化的能力增强;局部空化仅在一定条件范围内才会形成,空化范围受局部空化形成压力及冲击强度等因素的影响较大。

Wall pressure as a load parameter should be confirmed exactly, and then offered for investigating dynamic response of structure such as a plate subjected to underwater explosion. On the basis of plane shock wave hypothesis, a theoretical formula was deduced and proposed to calculate the wall pressure values of an infinite plate subjected to underwater explosion shockwaves at any angle of inci- dence. By using the wall pressure data derived from underwater explosion experiments, the theoretical formula of wall pressure was revised to be suitable for plates with finite dimensions. With the revised formula, the characteristics of the wall pressure on the plate were analyzed by considering various incidence angles, and the effects of the negative wall pressure values on local cavitation on the plate were discussed primarily. The results show that the wall pressure values derived from the revised formula agree well with those from the experiments. As the incidence angle increases, the wall pressure decays more rapidly, and the absolute value of the minimum wall pressure decreases. With the more explosive or the thicker plate, the absolute value of the minimum wall pressure is larger, and local cavitation takes place more likely. Local cavitation can only come into being in certain conditions,and the cavitation range will be affected by the factors such as cavitation pressure criterion, shock intensity, and so on.