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Title

Evolution of weakly nonlinear random directional waves: laboratory experiments and numerical simulations

Author(s)

Toffoli, A.;  Gramstad, O.;  Trulsen, K.;  Monbaliu, J.;  Bitner-Gregersen, E.;  Onorato, M.

Abstract

Nonlinear modulational instability of wavepackets is one of the mechanisms responsible for the formation of large-amplitude water waves. Here, mechanically generated waves in a three-dimensional basin and numerical simulations of nonlinear waves have been compared in order to assess the ability of numerical models to describe the evolution of weakly nonlinear waves and predict the probability of occurrence of extreme waves within a variety of random directional wave fields. Numerical simulations have been performed following two different approaches: numerical integration of a modified nonlinear Schrodinger equation and numerical integration of the potential Euler equations based on a higher-order spectral method. Whereas the first makes a narrow-banded approximation (both in frequency and direction), the latter is free from bandwidth constraints. Both models assume weakly nonlinear waves. On the whole, it has been found that the statistical properties of numerically simulated wave fields are in good quantitative agreement with laboratory observations. Moreover, this study shows that the modified nonlinear Schrodinger equation can also provide consistent results outside its narrow-banded domain of validity.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Engineering and Industrial Sciences

Source

Journal of Fluid Mechanics, Vol. 664, no. (2010), pp. 313-336

Publication year

2010

FOR Code(s)

0102 Applied Mathematics;  0915 Interdisciplinary Engineering

Keyword(s)

Euler equations;  Schrodinger equations;  Surface gravity waves;  Wavepackets

Publisher

United Kingdom

ISSN

0022-1120

Publisher URL

http://dx.doi.org/10.1017/s002211201000385x

Copyright

Copyright © Cambridge University Press 2010. Published version of the paper reproduced here in accordance with the copyright policy of the publisher.

Research Projects

Oceanic conditions within extreme tropical cyclones, Australian Research Council grant number LP0883888

Full text

Peer reviewed