Retrofitting of offshore cylindrical structures with different geometrical configuration of perforated outer cover

Presence of perforated members in ocean structures reduces the wave force on the damaged member because of the wave structure interaction; breakwaters with perforated members are classical examples of such kind. While retrofitting and rehabilitation is usually related to strengthening of members, the presented concept is a novel attempt as it addresses decrease in the encountered forces on the members. The present study is attempted numerically to quantify the force reduction on ocean structures encompassed by perforated outer covers with different geometric configuration of outer cylinder. Present study highlights the reduction of hydrodynamic response of perforated members under regular waves using numerical simulation. Hydrodynamic responses of cylinders with and without perforated cover are estimated for different sea states which are categorized as low, medium and steep wave steepness index. Based on the studies carried out, it is shown that there is average force reduction of about 60% is seen for the chosen geometric configuration. For this study the orientation of the structure under regular waves are also considered.