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Article Dans Une Revue Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences Année : 2021

Onset of energy equipartition among surface and body waves

Résumé

We derive a radiative transfer equation that accountsfor coupling from surface waves to body waves and the other way around. The model is the acoustic wave equation in a two-dimensional waveguide with reflecting boundary. The waveguide has a thin, weakly randomly heterogeneous layer near the top surface, and a thick homogeneous layer beneath it. There are two types of modes that propagate along the axis of the waveguide: those that are almost trapped in the thin layer, and thus model surface waves, and those that penetrate deep in the waveguide, and thus model body waves. The remaining modes are evanescent waves. We introduce a mathematical theory of mode coupling induced by scattering in the thin layer, and derive a radiative transfer equation which quantifies the mean mode power exchange. We study the solution of this equation in the asymptotic limit of infinite width of the waveguide. The mainresult is a quantification of the rate of convergence ofthe mean mode powers toward equipartition.

Dates et versions

hal-03147615 , version 1 (20-02-2021)

Identifiants

Citer

Liliana Borcea, Josselin Garnier, Knut Sølna. Onset of energy equipartition among surface and body waves. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2021, 477 (2246), pp.20200775. ⟨10.1098/rspa.2020.0775⟩. ⟨hal-03147615⟩
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