A Numerical Study Of Underwater Explosion Induced Water Waves And Their Effects On Nearby Marine Structures

Boundary element method based on potential flow theory has been developed to solve the waves induced by underwater explosion and their action on structures in the time domain.A fast algorithm for time-domain Green function at infinite depth and its derivatives are presented for following calculations.Next, based on the assumption of a simple bubble model (Rayleigh bubble model), bubble dynamics equations have been established for the source strength of the bubble pulsation.Water waves caused by underwater explosion have been simulated by the evaluations of time-domain Green function with the source strength replaced by the bubble pulsation on the basis of potential flow theory.Then the actions of underwater explosion induced water waves on fixed structures have been numerically analyzed. The calculation model is first examined by the diffraction of simple shape body (hemi-sphere and truncated cylinder) in regular waves. The computed wave forces are compared with the frequency-domain results, and they agree very well. The diffraction problems of fixed structures under waves caused by underwater explosion are considered next. A relationship between wave forces and explosive charge or explosive embedment depth or horizontal distance between explosive source and structures has been studied later.Finally, diffraction-radiation problems are examined in context of simple shape body (submerged sphere and floating box) and compared with the frequency-domain results. The parameter analysis of explosive charge, explosive embedment depth and horizontal distance between explosive source and structures is implemented.