3D Computational Fluid Dynamic Investigation on Wave Transmission behind Low-Crested Submerged Geo-Bag Breakwater

Abstract

Wave transmission characteristics behind low-crested submerged breakwaters involve complex-hydrodynamic interaction of water waves on the structures. To properly comprehend the induced-nonlinear wave transformation, the problem necessitates a trustworthy prediction using a computational fluid dynamic (CFD) technique. The goal of this study is to develop a three-dimensional (3-D) computational model of the hydrodynamic performance of a narrow crest behind a submerged breakwater in order to gain a thorough understanding of the wave transmission coefficient, K_t. The simulation took into account a number of wave parameters such as wave steepness (H_i⁄L), relative submergence depth (H_i⁄h), and crest width (c_w⁄L) of the structure. A numerical wave flume model is included, which is based on the full Navier-Stokes solver and includes a shallow water model to account for nonlinearity in the incident wave field. In addition, laboratory measurements were also conducted using a geo-bag dike model as the main breakwater structure. The result shows that the reduction in transmission coefficient correlates highly with the wave steepness and the relative submergence and crest parameters. This can be attributed to most breaking waves over the submerged breakwater. The steeper the incident wave, the greater the reduction in the transmitted wave. And, the greater the principal dimensions of the breakwater, the greater the drop in transmission coefficient. For validation, the CFD results corroborate satisfactorily with measurements