Flow field around outer perforated circular cylinder under regular waves: numerical study

Offshore structures are often subjected to critical environmental loads that cause serious damage; MARS TLP in Gulf of Mexico damaged by hurricane Katrina in 2005 is an example. Existence of external perforated cover reduces hydrodynamic forces on the existing members caused by direct wave impact. The quantification of the force reduction in the offshore structures is reported by many researchers by emphasizing the fact that there is reduction in force on the existing member due to the presence of outer perforated cover. From the existing literature, the annular spacing and the perforation ratio are taken as 0.5 and 11 %. Velocity profile in the cylinder and around the perforation is investigated to give a better understanding of the physics for the considered case. Variation of velocity is also studied along the depth of cylinder and also in the perforation zone to get the clear understanding of the physics using the computational fluid dynamics tool STAR-CCM+ for various areas of perforation for different wave steepness (H/L).