Interaction between waves and current on a two-dimensional body in the free surface

Interaction is studied between incident regular waves and current on an infinitely long horizontal cylinder piercing the free surface. A theory to first order in wave amplitude and current velocity is developed and a new numberical procedure is presented to solve the first order problem. A generalized Haskind relation for the wave excitation force is derived. It is shown to be important that the waves interact with the local steady flow and that current has an important effect on mean wave drift forces. Wave-drift damping is evaluated and shown to be important.