Calculation of Wave Forces on Structures using REEF3D

Abstract

Non-breaking wave forces on a cylindrical pile placed on a platform were calculated numerically by solving the 3D Navier Stokes equations in the Numerical Wave Tank of REEF3D. Initially, the numerical wave tank was validated by comparison of the numerical results with the analytical solutions for varying grid density, time step size, numerical beach width, wave amplitude, numerical method- time and spatial discretization, relaxation method and wave type. The performance of the wave tank under the aforementioned various conditions was observed. As a result the appropriate parameters to be used for the numerical experiment were obtained. Finally, simulations were carried out to calculate the wave forces on a cylindrical pile and the numerical results were compared to the results obtained using the Morison formula.During validation, it was observed that the wave tank gives good results with an error of 0.24% in the wave amplitude at a grid density of 100 cells per wavelength and CFL number 0.1. A recent study using a different approach reported a requirement of 200 cells per wavelength. Thus, the performance of the wave tank in this study is considered very good. The calculation of wave forces also showed a good match to the theoretical result. There were no instabilities in the solution from the numerical calculations.