Interaction between an external shock wave and a cylindrical shell filled with and submerged into different fluids

A submerged fluid-filled cylindrical shell subjected to an external shock wave is addressed for the most general case when the internal and external fluids have different properties. Three distinctly different scenarios of interaction are identified depending on the parameter ζζ defined as the ratio of the acoustic speed in the internal fluid to that in the external one. The first scenario corresponds to the values of ζζ below unity, and it can follow two sub-scenarios that exhibit qualitatively different focusing and reflection sequences, with the transition between the sub-scenarios occurring at ζ≈0.52ζ≈0.52. The second scenario, ζ=1ζ=1, corresponds to the relatively well-studied case of two identical fluids, yet some interesting, previously unreported effects are observed for such ζζ as well. The third scenario corresponds to the values of ζζ above unity, and it also exhibits a number of unique features of the wave propagation and reflection. The dynamics of the complete internal-external field is visualized and analyzed for the three scenarios, with the emphasis on both the theoretical significance of the effects observed and their practical implications.