Two-Dimensional Numerical Analysis of Submerged Dike Hydrodynamics

Many studies have been conducted on wave and sediment movement with submerged dikes. However, the effect of a submerged dike’s height and orientation on hydrodynamics has not been thoroughly examined from the perspective of the marine ecology impact. This paper employs a two-dimensional numerical model to investigate effects of submerged dike height and orientation on flow, specifically flow velocity and cross-dike flux. The findings indicate that the most significant velocity variation occurs at a distance of approximately one-fifth of the dike length (0.2 L) from the dike head, when the flow is perpendicular to the dike and parallel to the coastline. And this area as the submerged dike’s protection zone will have the least impact on the surrounding environment. The change pattern of the flow velocity with the distance apart from the submerged dike varies for different submerged dike heights. A submerged dike height of 0.7 times the water depth (0.7 H) is a dividing value. Additionally, as the orientation angle increases, the cross-dike flux rises. From the perspective of the impact on the marine ecological environment, the design angle of the submerged dike should be as small as possible. The findings establish a theoretical hydrodynamic basis that may support future integrated studies on coastal zone management.