Shock response of a two-fluid cylindrical shell system containing a rigid core

• A shell with different fluids inside and outside is enhanced with an internal core.
• Such a model allows for more realistic simulations of industrial systems.
• Fundamental differences from the case of identical fluids are observed.
• Suggestions for facilitating pre-design analysis of industrial systems are given.

A submerged fluid-filled cylindrical shell containing a rigid co-axial core and subjected to an external shock wave is considered, and the fluid dynamics of such interaction is analyzed for the most general scenario of two different fluids. It is demonstrated that the phenomenology of the interaction in this case is fundamentally different from the case when the fluids are identical. In the latter case, all the most important wave propagation, reflection and focusing phenomena in the internal fluid that are observed for the shell without a core are also present when a core is placed inside the fluid, unless the core directly occupies the region of the fluid where the phenomena occur. When the fluids are different, however, it is possible that some phenomena are not observed even when the core does not occupy the respective region of the fluid. Due to the very high pressure that is often associated with the phenomena in question, this observation is of considerable practical significance in that it suggests the possibility of a very significant reduction of the peak pressure in the system by means of placing an additional structure inside the primary shell. The observations made are quantified using a number of pressure time-histories aimed at facilitating the pre-design analysis of shock-subjected fluid-interacting structures.