Numerical study on hydrodynamic characteristics, wave forces and dynamic responses of offshore jacket platform under tsunami-like solitary waves

Offshore platforms as most widely used equipment in oil and gas production are facing challenges from extreme tsunamis, causing serious damage or even catastrophic consequence. This paper aims to investigate the dynamic responses of offshore jacket platform considering the fluid-structure interaction (FSI) between tsunamis-like solitary wave and the platform using the CFD-FEA coupling method. The 3D numerical wave tank with a jacket platform is constructed. Three different solitary waves are simulated to examine the effect of wave nonlinearity, among which two typical flow patterns are recognized. Special attention is paid to detailed analysis of distinct hydrodynamic phenomena during wave evolution and wave forces distribution when waves impacting the platform. Furthermore, structural responses are analyzed in both time domain and frequency domain. The results show that when the jacket platform is subjected to solitary waves, it is more prone to produce high frequency resonance in horizontal direction than in vertical direction. Moreover, the effect of wave nonlinearity plays important role on the structural responses including displacement, von-Mises stress, and inter-layer drift ratio (IDR), which will affect the operating safety of the platform against tsunami-like waves. This study gives guidance for assessing disaster resistance of platforms subjected to extreme wave loading.