Effect of External Water Flow on Response of Cylindrical Shell Subjected to Under Water Explosion

This article deals with response of cylindrical shell subjected to loading of Under Water Explosion (UNDEX) when water current is introduced to the surrounding environment. Cylindrical shells as one of main basic structural elements in construction of marine and submarine facilities are prone to UNDEX threat. Due to vicissitudes of conducting experiments in this field and also complicated inherent of fluid-solid interaction phenomenon, numerical models can be used as an effective tool for scrutinizing the problem. In this study, a submerged thin walled cylindrical shell and its surrounding water discretized by coupled shell Lagrangian elements and Eulerian cells respectively. Simulations are performed in AUTODYN hydrocode. For better perceiving of phenomenon, studies are done for two various explosive charge stand-off distances. Results show that introduction of flow to water, can tangibly change the symmetrical configuration of flow- less problem. Due to intricate interaction of water flow and explosion bubble, distribution of UNDEX overpressure and impulse is disturbed and this leads to un-symmetric deformation of cylindrical shell. Also amplitudes of deflection are reduced obviously by increasing flow velocity.