Analysis of wave fields generated by a directional wavemaker

Directional wavemakers, which consist of numerous individually programmed paddles mounted along one wall of a wave basin, have become more available in the past five years for the study of wave and structure interaction. The waves generated by these wavemakers differ from those in nature, as the motion of the wavepaddle does not correspond to the motions of the water particles under a progressive wave train. The result of the mismatch in particle motion and wave paddle motion are a set of standing waves, which are confined within the vicinity of the paddle, and free waves, which propagate in a direction different from the desired progressive waves. Using a perturbation analysis, a second-order solution is obtained for the wave field generated by a directional wavemaker. Experimental observations, using maximum likelihood analysis, verifies the predictions of the free wave direction.