Cavitating bubbly flows can form in separated flows and shear layers leading to local regions high vapor void fraction, and these flows often exhibit periodic shedding of vaporous clouds. Historically, the presence of a liquid re-entrant flow, driven by the kinematics of liquid flow stagnation, has been identified as an important mechanism leading to cavity shedding. However, high local vapor void fractions can also result in a reduced mixture speed of sound and a possible supersonic flow. Our recent findings on different geometries indicate that propagating bubbly shocks in these flows are a primary mechanism of flow instability. In this study, we discuss the effect of compressibility on four geometries, mainly in the generation of propagating bubbly shocks that can influence the cavitation shedding dynamics. In order to elucidate the differences and similarities of the observed cavitation dynamics, and the influence of compressibility, we report observations from a backward facing step, backward facing wedge, NACA0015 hydrofoil, and a bluff body with a wedge cross section.

中文翻译：

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可压缩性对气泡空化流的影响

空化的气泡流可以形成在分开的流和剪切层中，从而导致局部区域具有较高的蒸气孔隙率，并且这些流通常表现出周期性的气态云散发。历史上，由液体流动停滞的运动学驱动的液体折返流的存在已被认为是导致空腔脱落的重要机制。但是，较高的局部蒸气空隙率也可能导致声音的混合速度降低，并可能产生超音速流动。我们最近对不同几何形状的发现表明，在这些流动中传播的气泡冲击是流动不稳定的主要机制。在这项研究中，我们讨论了可压缩性对四个几何形状的影响，主要是在传播气泡的冲击的产生中，气泡的冲击会影响空化脱落动力学。