Experiments and numerics of bichromatic wave groups

This paper reports on extensive experiments on nonlinear wave groups that e volve in a hydrodynamic laboratory over long distances (200 m) from the gen eration of simple bichromatic waves. The deepwater experiments show large d eformations of the wave group, with large increase of wave heights, dependi ng on the value for the quotient of wave amplitude and frequency difference . The experimental results show little dissipation and reflections are virt ually absent. A very efficient and accurate numerical code based on the ful l nonlinear surface wave equations, which has been developed for this purpo se, reconstructs the experiments and enables one to investigate the evoluti on over much longer distances (reported here until 1,200 m) than in the lab oratory.