Three-dimensional flow characteristics around permeable submerged breakwaters with open inlet

Abstract

We analyzed the three dimensional hydrodynamic characteristics around fully submerged dual breakwaters with a sandy beach using a newly developed three-dimensional numerical scheme. Using our model which considers wave-structure-sandy seabed interactions in a 3-D wave field, we were able to determine the direct effects of the porous media of submerged breakwaters and a sandy beach on the flow characteristics. We also used a large eddy simulation with a sub-grid scale model to compute eddy viscosity. The numerical analysis reveals that relatively large circular flows around the ends of the submerged breakwaters are generated, and that the magnitudes of these flows depend on the difference in the mean surface elevation between offshore and onshore. Three-dimensional analyses of the mean flow and the mean vorticity in the x-y, x-z, and y-z planes reveal patterns quite different from those revealed by prior 2-D numerical analysis studies. The distributions of wave breaking point and mean surface elevation around the submerged breakwaters are also analyzed and discussed in detail. (C) 2012 Elsevier Ltd. All rights reserved.