From modulational instability to focusing dam breaks in water waves

摘要: We report water wave experiments performed in a long tank where we consider the evolution of nonlinear deep-water surface gravity waves with envelope form large-scale rectangular barrier. Our reveal that, for range initial parameters, packet is not disintegrated by Benjamin-Feir instability but exhibits specific, strongly modulation, which propagates from edges toward center finite speed. Using numerical tools spectral analysis experimental data, identify observed structures focusing dispersive dam break flows, peculiar type shock recently described framework semiclassical limit 1D Schrodinger equation (1D-NLSE). results are shown to be good quantitative agreement predictions 1D-NLSE theory. This first observation persisting dynamics modulationally unstable system.