The Performance Evaluation of a Floating Pontoon with Triple Vertical Porous-Membrane Breakwater in the Oblique Seas

Hydrodynamic characteristics of floating pontoon breakwater with triple vertical porous membranes are investigated in the context of two-dimensional linear wave-flexible body interaction theory. The vertical-porous-membrane structures hinged with spacing at the bottom of a floating pontoon and also hinged at some distance from the seabed. The tensions in the membranes are achieved by a net buoyancy force of submerged volume of pontoon. A floating structure is partially restrained by linear symmetric moorings for and aft. The restoring and exciting force and moment of pontoon by the tip displacements of membranes has been formulated with appropriate boundary conditions. The BEM program is developed based on a discrete membrane dynamic model and simple-source (second-kind modified Bessel function) distribution over the four sub-fluid domain boundaries. Since the boundary condition on the membrane is not known in advance, the membrane motions and velocity potentials in each region are solved simultaneously. It is found that a properly moored floating pontoon breakwater with long vertical porous membranes that take major fraction of water can significantly increase the overall wave blocking efficiency in normal and oblique incident waves including long wave regions.