Numerical study on a hybrid water wave radiation condition by a 3D boundary element method

Based on the constant boundary element method in a 3D numerical wave tank, a hybrid radiation condition which is the composition of the multi-transmitting formula (MTF) method and the damping zone is studied. Numerical solutions show excellent agreements with the analytical ones, which verify the effectiveness of the hybrid method. This method can be considered as a trimming of the MTF condition, or an extension of the damping zone method, and has good ability of simulating irregular waves with relatively large frequency span.

► A 3D numerical wave tank by the boundary element method is modelled to study water wave radiation conditions.
► Drawbacks are found in two conventional radiation conditions (multi-transmitting formula method and damping zone).
► A hybrid method is effective to overcome their main drawbacks.
► The hybrid method can simulate irregular waves with relatively large frequency span effectively.