Current effects on nonlinear wave slamming by an Oscillating Wave Surge Converter

A time-domain higher-order boundary element method (HOBEM) based on potential theory with fully nonlinear boundary is developed to simulate an Oscillating Wave Surge Converter (OWSC) rotating in waves in the presence of uniform currents. A domain decomposition method which neglects impact of jet flow to the main flow field is adopted. Auxiliary function is used to calculate the pressure distribution on body surface. The rotating coordinate system with origin fixed at the rotating center is established to avoid the water particle moving into or away from the body during the simulation. An iteration method is employed to assess the values of coupling wave characteristics affected by currents. Good agreement is found between present model and published fist-order boundary element method (FOBEM) model for the interaction of flap and current-free waves. Numerical simulations are then conducted in the presence of following current, opposing current and zero current, respectively. Several parametric studies, such as angle velocity and angular acceleration of the flap, initial phase, wave height and wave length, are performed to study the characteristics of the slamming problem with taking into account currents effects. The numerical results are presented through free surface profiles and pressure distributions.