수직실린더에 작용하는 충격력 수치해석

Abstract

The impact forces of the highly nonlinear waves are one of the important factors in designing the ocean structures. The impact forces are very difficult to analyze numerically and experimentally because they are impulsive in magnitude and occur instantaneously. In this study, the numerical program based on N.S. equations are used to investigate the impact forces of steep waves where the waves are generated by the wave maker in the numerical wave basin. To validate the numerical code, waves of single frequency are generated and compared with the analytic solution. The arbitrary steep waves are generated by the superposition of each waves and the results are compared with experimental ones, and the acceptable agreements are found. The impact forces on vertical cylinder are simulated where the multiblock grid are applied to cover the complex geometries. The simulations are carried out with varying time steps and grid size near the vertical cylinder, but the incoming breaking waves near the vertical cylinder are not suitably formed, and the magnitudes of the forces show very low values. It is thought that the incoming breaking waves should be simulated near the vertical cylinder more accurately and the impact modeling of the duration time should be made to obtain more reasonable results.