Mohamad Javad Ketabdari - Amirkabir University, of Technology, Tehran, Iran
Alireza Allahverdi - Amirkabir University, of Technology, Tehran, Iran

Risers are one of the most important components of offshore structures. The main task of the marine risers is transporting oil from the seabed to water surface. Because of the wave and current forces in the risers various forces affect these components causing their deformation. Marine risers often used in a group and the arrangement of groups risers effect on the drag and lift forces exerted to them due to waves and currents. In this study different variants were examined for modeling wave and riser interaction in order to determine the optimum arrangement for drag and lift forces.