The Peregrine breather (PB) is a rational solution of the nonlinearSchrödinger equation (NLS). PB is localized in both space and time,culminates in the amplification that is three times the initial waveamplitude. Therefore, it is often considered to be an appropriateprototype of rouge waves in ocean. However, until now, there are someresearches on the evolution of PB of ocean gravity waves, butexperimental observation of the PB in a wave flume is still lacking,especially investigations on the influence of water depth on theevolution of PB. In the present study, detailed measurements forpropagation of PB with different initial steepness were conducted in awave flume. Higher harmonics significantly contribute the surfaceelevations at the place where the PB solution reaches the maximumamplitude. But the contribution of higher harmonics on surfaceelevations reduces with increasing water depth. The experimentalresults are in a very good agreement with the PB up to the shortdistance from the wave maker, at further distances, differences betweenthe theory and the experiment start to appear. The third order solutionof the NLS agrees well with experiments. The maximum envelopeamplification in the experiments is slightly below that predicted by thePB; the discrepancy reduces with increasing water depth.
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