Wave interaction with low-mound breakwaters using a RANS model

Abstract Using COBRAS-UC, a numerical model based on the Volume-Averaged Reynolds Average Navier–Stokes (VARANS) equations, 2-D wave interaction with low-mound breakwaters is analyzed. The model uses a Volume of Fluid (VOF) technique method to capture the free surface which allows the modeling of complicated processes such as breakwater overtopping. Furthermore, thanks to the VARANS equations, the flow in the permeable layers underneath the caisson is quantitatively correct. In order to validate the model's performance, a new set of experimental studies are carried out in a wave flume at a 1:20 scale using regular and irregular waves. Comparisons between numerical and experimental free surface, pressure time histories, and overtopping layer thickness for regular and irregular waves show a good agreement. Further comparisons of numerically predicted overtopping magnitudes with existing semi-empirical formulae and experimental data indicate that the model can be used as a complementary tool for the functional design of this kind of structures.

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