Scattering of Water Waves by Two Rows of Submerged Vertical Cylinders

This study examines the hydrodynamic performance of an alternative submerged breakwater consisting of two rows of submerged vertical cylinders. An analytical solution based on the linear potential theory and the matched eigenfunction expansion method is developed for the scattering of water waves by the structure. The reflection coefficient, the transmission coefficient and the wave force acting on each row of cylinders are calculated. The present numerical results of reflection and transmission coefficients for limiting cases are the same as the previous predictions of single submerged impermeable or permeable barrier and two rows of submerged impermeable barriers. Numerical examples indicate that with suitable design the reflection and transmission coefficients of the breakwater may be simultaneously small. At the same time, the wave force acting on each row of cylinders is also small. Numerical examples also demonstrate that interchanging the two rows of vertical cylinders do not vary the transmission coefficient of the breakwater.