NUMERICAL SIMULATION AND ANALYSIS OF PHASE FOCUSED BREAKING AND NON-BREAKING WAVE IMPACT ON FIXED OFFSHORE PLATFORM DECK

Extreme wave impact due to tsunamis and storm surge create large wave heights causing destruction to coastal and offshore structures. These extreme waves are represented by focused waves in the present study and the impact on offshore deck is studied. Numerical wave tank used is modelled using open-source software REE3D, where the level set method is used to capture the air-water interface. Vertical impact force on offshore deck is computed and compared with the experimental results to validate the numerical model. Focused wave is generated by phase focusing a group of waves at a particular position and time. The nonlinearity of focused wave and its effect on the vertical impact force is quantified for different airgap and increasing wave heights. The steepness of this focused wave is increased to initiate phase focused breaking in the numerical wave tank, which is validated with experimental results of Ghadirian et al., 2016. The main purpose of this paper is to examine breaking focused wave group loads on the offshore deck and to study the impact on deck at different breaking locations. The positioning of the deck with respect to breaker location have shown that the maximum horizontal impact force due to breaking wave occurs when the plunging crest hits the deck side.