Hydrodynamic behaviour of floating polygonal compound platforms with wide porous media

Abstract

Presented herein are the formulation and semi-analytical solutions for the hydrodynamic characteristics and wave fields of floating polygonal compound platforms with wide porous media. The wetted porous medium is assumed to be homogeneous and fully saturated. Limiting cases of the semi-analytical solutions without the porous medium have been verified by the results obtained by using the commercial software ANSYS AQWA. The present semi-analytical solutions based on a matched eigenfunction expansion method are useful as benchmark results for analysts working on new numerical methods for the hydrodynamic analysis of floating platforms with porous media. Parametric studies were conducted to examine the effects of porous media on the wave exciting forces, RAOs, wave fields, porous damping and mooring loads. It is found that the wide porous medium with appropriate porosity and resistance coefficient contributes to reducing the wave exciting forces, RAOs, and overall level of wave fields in the long period region by attenuating the incident wave energy. Also, the porous medium helps to decrease the mooring loads, especially at resonance. Thus, a wide porous medium surrounding the compound platform is effective in both enhancing the motion performance of the floating platform and reducing the wave fields around it.