The instability of the vertically-stratified horizontal plane Poiseuille flow

P Le Gal (1) , U Harlander (2) , I Borcia (2, 3) , Stéphane Le Dizès (1) , J Chen (1) , B Favier (1)

1 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre
2 Department of Aerodynamics and Fluid Mechanics
3 Institute of Physics

We present here the first study on the stability of the plane Poiseuille flow when the fluid is stratified in density perpendicularly to the plane of the horizontal shear. Using laboratory experiments, linear stability analyses and direct numerical simulations, we describe the appearance of an instability that results from a resonance of internal gravity waves and Tollmien-Schlichting waves carried by the flow. This instability takes the form of long meanders confined in thin horizontal layers stacked along the vertical axis.

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

P Le Gal, U Harlander, I Borcia, Stéphane Le Dizès, J Chen, et al.. The instability of the vertically-stratified horizontal plane Poiseuille flow. Journal of Fluid Mechanics, 2021, 907, pp.R1. ⟨10.1017/jfm.2020.917⟩. ⟨hal-02978216⟩