Numerical Modeling of Compression Waves for Hypersonic Shock-Cylinder Interaction with Cavitation

The interaction between shock waves and water droplets has been investigated both numerically and experimentally. Current and historical results have shown that when the shock wave impacts a droplet, a compression wave is induced inside the droplet and will reflect off the interface between the liquid and air. Since the back face of a droplet is curved, it will act like a hemispherical lens that focuses the reflected compression wave to a point of super low pressure where cavitation phenomena has a high probability of occurring. Depending on the shock Mach number, the internal compression wave can attain different shapes as it progresses through the droplet. This effort will aim to model the shock water column interaction phenomenon numerically, focusing on understanding how the curvature of the induced compression wave inside a water column will affect the cavitation event that occurs inside the water droplet. The numerical simulation is performed using the commercial code STAR-CCM+. The different phases are modeled using the Volume of Fluid (VOF) Method. The cavitation phenomena is modeled using the Full Rayleigh-Plesset (FRP) equation. Results from this effort have shown that the cavitation event significantly alters the reflection of the compression wave by preventing it from reflecting at all. While the shape of the compression wave alters the shape of the cavitation region. The results from this effort will contribute additional understanding into this complex phenomenon.