An unstructured FEM model based on Boussinesq equations and its application to the calculation of multidirectional wave run-up in a cylinder group

In this paper, a numerical model based on the improved Boussinesq equations derived by Beji and Nadaoka [5] is first developed using unstructured finite element technique. A locally rotated coordinate system is introduced to improve the treatment for the fully reflective boundaries whose orientation does not coincide with the coordinate system. The Adams–Bashforth–Moulton predictor–corrector scheme is used for time integration. Typical examples are employed to validate the numerical model. Based on the developed model, multidirectional wave propagation through a cylinder group is numerically calculated and the effects of the wave directionality on the waves in the group and the wave run-up on the cylinders are investigated. Numerical results show that the wave directionality has considerable effect on the wave run-up in the cylinder group.