Interactions of Horizontal Porous Flexible Membrane with Waves

Abstract

The interaction of monochromatic incident waves with a horizontal porous flexible membrane is investigated in the context of a 2D linear hydroelastic theory. First, a multidomain boundary element method is developed for a porous membrane based on Darcy's fine-pore model. The inner solution uses a discrete membrane dynamic model and simple-source distribution over the entire fluid boundaries. The outer solution is based on an eigenfunction expansion method. The inner solution is then matched to the outer solution at the matching boundaries. Second, the corresponding analytic diffraction and radiation solutions are obtained based on the multidomain eigenfunction expansion method to better understand the relevant physics and confirm the boundary element method results. Using the developed computer program, the wave-blocking performance of a submerged horizontal porous membrane is tested with various system parameters, membrane porosity, and wave characteristics. The wave numbers above the porous membrane are generally complex, and the imaginary parts contribute to the dissipation of wave energy. Therefore, the overall performance of the horizontal flexible membrane can be further enhanced by using proper porous material. The theory and numerical results are also verified through a series of model tests in a 2D wave tank.