Acoustic and gravity waves in the ocean: a new derivation of a linear model from the compressible Euler equation

Juliette Dubois (1) , Sébastien Imperiale (2) , Anne Mangeney (3) , François Bouchut (4) , Jacques Sainte-Marie (1)

1 ANGE - Numerical Analysis, Geophysics and Ecology
2 M3DISIM - Mathematical and Mechanical Modeling with Data Interaction in Simulations for Medicine
3 IPG Paris - Institut de Physique du Globe de Paris
4 LAMA - Laboratoire Analyse et de Mathématiques Appliquées

In this paper we construct an accurate linear model describing the propagation of both acoustic and gravity waves in water. This original model is obtained by the linearization of the compressible Euler equations, written in Lagrangian coordinates. The system is studied in the isentropic case, with a free surface, an arbitrary bathymetry, and vertical variations of the background temperature and density. We show that our model is an extension of some models from the litterature to the case of a non-barotropic fluid with a variable sound speed. Other models from the literature are recovered from our model through two asymptotic analysis, one for the incompressible regime and one for the acoustic regime. We also propose a method to write the model in Eulerian coordinates. Our model includes many physical properties, such as the existence of internal gravity waves or the variation of the sound speed with depth.

Domaines: Mécanique des fluides [physics.class-ph]; Equations aux dérivées partielles [math.AP]; Océan, Atmosphère

Juliette Dubois, Sébastien Imperiale, Anne Mangeney, François Bouchut, Jacques Sainte-Marie. Acoustic and gravity waves in the ocean: a new derivation of a linear model from the compressible Euler equation. 2023. ⟨hal-03880423v3⟩