This study focuses on the computation and analysis of the energy content of a wave train and the influence of nonlinear components, such as nonlinear wave profile as in Stokes wave and phased locked breathers, on the content. To this end, an overview of a state-of-the-art nonlinear Fourier analysis tools for the nonlinear Schrödinger equation is presented. Experimental measurements from a set of performance tests of the directional wave basin at Oregon State University were analyzed using this tool and the energy contents, both from the linear spectrum and nonlinear spectrum, were calculated. The deviation of the energy content from linear analysis and its relationship to the level of nonlinearity of the wave train is investigated. The Benjamin-Feir parameter presents the degree of nonlinearity of the wave train. An increasing energy deviation was observed for increasing nonlinearity of the wave field. Spatial evolution of such behavior is also investigated. It was confirmed that the significant difference from the linear energy is due to increase in the nonlinear components and the more distance the wave train could travel (without substantial dissipation) the more erratic and more significant energy deviations were observed.

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