Numerical simulations of a twin-square marine structure with different submerged depths and gap ratios in waves

Abstract

The wave-structure interactions for a twin-square structure with different submerged depths and gap ratios are investigated using a 2D numerical tank based on the Unsteady Reynolds-averaged Navier-Stokes equations with the k−ω SST turbulence model. The volume of fluid method is employed to capture the characteristics of the free surface. The wave past a horizontal circular structure is simulated to validate the present numerical model by comparing the numerical results with the experimental data measured by Dixon et al. (1979). Then, the hydrodynamic characteristics of a twin-square structure in waves are investigated using the validated numerical model, including wave forces, free surface elevations and vortex structures. The influences of the twin-square structure’ submerged depth and gap ratio on its hydrodynamic characteristics are studied. The numerical results show that both submerged depth and gap ratio have significant influences on the wave forces acting on and the flow field around the structure. The structure is easily subjected to the wave impact loads when it is located above the still water level. When the gap ratio is less than 0.6, the vertical wave forces on the structure decrease with the increase of the gap ratio. The influence of the gap ratio is considered to be negligible when the gap ratio is larger than 0.6.