Evolution of a nonlinear wave field along a tank: experiments and numerical simulations based on the spatial Zakharov equation

Evolution of a nonlinear wave field along a laboratory tank is studied expe rimentally and numerically. The numerical study is based on the Zakharov no nlinear equation, which is modified to describe slow spatial evolution of u nidirectional waves as they move along the tank. Groups with various initia l shapes, amplitudes and spectral contents are studied. It is demonstrated that the applied theoretical model, which does not impose any constraints o n the spectral width, is capable of describing accurately, both qualitative ly and quantitatively, the slow spatial variation of the group envelopes. T he theoretical model also describes accurately the Variation along the tank of the spectral shapes, including free wave components and the bound waves .