Andrei Pushkarev

Quasibreathers in the MMT model

Abstract We report numerical detection of a new type of localized structures in the frame of Majda–McLaughlin–Tabak ( M M T ) model adjusted for description of essentially nonlinear gravity waves on the surface of ideal deep water. These structures–quasibreathers or oscillating quasisolitons–can be treated as groups of freak waves closely resembling experimentally observed “Three Sisters” wave packets on the ocean surface. The M M T model has quasisolitonic solutions. Unlike N L S E solitons, M M T quasisolitons are permanently backward radiating energy, but nevertheless do exist during thousands of carrier wave periods. Quasisolitons of small amplitude are regular and stable, but large-amplitude ones demonstrate oscillations of amplitude and spectral shape. This effect can be explained by periodic formation of weak collapses, carrying out negligibly small amount of energy. We call oscillating quasisolitons “quasibreathers”.

Limited fetch revisited: Comparison of wind input terms, in surface wave modeling

The results of numerical solution of the Hasselmann kinetic equation (

The kinetics of three-dimensional Langmuir collapse

HE

On the Tuning-Free Statistical Model of Ocean Surface Waves

) for wind driven sea spectra in the fetch limited geometry are presented. Five versions of the source functions, including recently introduced ZRP model, have been studied for the exact expression of Snl and high-frequency implicit dissipation due to wave-breaking. Four out of five experiments were done in the absence of spectral peak dissipation for various Sin terms. They demonstrated the dominance of quadruplet wave-wave interaction in the energy balance and the formation of self-similar regimes of unlimited wave energy growth along the fetch. Between them was ZRP model, which showed especially good agreement with the dozen of field observations performed in the seas and lakes since 1971. The fifth, WAM3 wind input term experiment, used additional spectral peak dissipation and reproduced the results of previous similar numerical simulation, but was in a good agreement with the field experiments only for moderate fetches, demonstrating total energy saturation at the level twice as lower as Pierson-Moscowits limit. The alternative framework for

Comparison of Different Models for Wave Generation of The Hasselmann Equation

HE

Deterministic and Advanced Statistical Modeling of Wind-Driven Sea

numerical simulation is proposed along with the set of tests allowing to select physically justified source terms.