Abstract
A theoretical hydrodynamic formulation is presented for wave interactions on structures composed by permeable and impermeable surfaces. The idea conceived, is based on the capability of permeable bodies to dissipate the wave energy and to minimize the environmental impact, developing wave attenuation and protection. In this study the diffraction problem of water waves by a permeable vertical, sea bottom seated, cylindrical body is formulated within the framework of the linear potential theory. The results revealed that porosity plays a key role in reducing/controlling the exciting wave loads, hence porous barriers can be set up to protect a marine structure against the wave attack.