WAVES GENERATED BY A PLUNGER-TYPE WAVE-MAKER

Abstract

Based on a two dimensional linear water wave theory, the boundary element method (BEM) is developed and applied to study the waves generated by a plunger-type wavemaker. The computational domain is truncated by introducing two auxiliary boundaries at three times wave length distance away from the wavemaker. Radiation condition is used along the auxiliary boundaries. The accuracy of the numerical technique is demonstrated by comparing numerical results with previously published results, experimental and other techniques. However the actual wave height is smaller in the experiments than predicted by numerical models. The discrepancy between predicted and observed wave height can be attributed to the effects of leakage of wave energy under the plunger-type wavemaker. In order to predict waves generated by plunger-type wavemaker accurately, the influence of leakage, under the plunger-type wavemaker, is included in the present study. The ratios between wave amplitude and stroke are established for two different conditions, with and without leakage. The agreement between the numerical solutions and laboratory data is quite good.