Long-time dynamics of internal wave

Timothée Jamin (1) , Takeshi Kataoka , Thierry Dauxois (1) , T R Akylas

1 Phys-ENS - Laboratoire de Physique de l'ENS Lyon

The mean flow induced by a three-dimensional propagating internal gravity wave beam in a uniformly stratified fluid, is studied experimentally and theoretically. Previous related work concentrated on the early stage of mean-flow generation, dominated by the phenomenon of streaming-a horizontal mean flow that grows linearly in time-due to resonant production of mean potential vorticity (PV) in the vicinity of the beam. The focus here, by contrast, is on the long-time mean-flow evolution. Experimental observations in a stratified fluid tank for times up to t = 120 T 0 , where T 0 is the beam period, reveal that the induced mean flow undergoes three distinct stages: (i) resonant growth of streaming in the beam vicinity; (ii) saturation of streaming and onset of horizontal advection; and (iii) establishment of a quasi-steady state where the mean flow is highly

Domaines: Mécanique des fluides [physics.class-ph]

Timothée Jamin, Takeshi Kataoka, Thierry Dauxois, T R Akylas. Long-time dynamics of internal wave. Journal of Fluid Mechanics, 2021, ⟨10.1017/jfm.2020.806⟩. ⟨hal-03381656⟩