WAVE DIFFRACTION AROUND 3-DIMENSIONAL BODIES IN A CURRENT

The effects of a collinear current on the diffraction of regular waves around three-dimensional surface-piercing bodies are examined. With t he current speed assumed to be small, the boundary-value problem is se parated into a steady current problem with a rigid wall condition. app lied at the still water level and a linear wave propagation problem in the resulting current field The boundary conditions of the wave propa gation problem are satisfied by a time-stepping procedure and the fiel d solution is obtained by an integral equation method. Free surface pr ofiles, runup, and wave forces are described for a vertical circular c ylinder in combined waves and a current. The current is shown to affec t significantly the steady drift force and runup predictions. Comparis ons of the computed wave forces are made with a previous numerical sol ution involving a semi-immersed sphere in deep water, and indicate goo d agreement.