EXPERIMENTS ON NONLINEAR-WAVE GROUPS IN INTERMEDIATE WATER DEPTH

Evolution of nonlinear wave groups of various initial envelope shapes is studied experimentally in a wave tank. Experiments are performed fo r different values of the water depth in the tank. The experimental re sults are compared with the calculations based on the cubic Schrodinge r equation. Qualitatively different results are obtained for water dep th values corresponding to different signs of the nonlinear term coeff icient in the model equation. In relatively shallow water, the demodul ation of wave groups is observed, while in a deeper water the maximum wave height increases along the tank due to the focusing, as expected.