title: Reverse transition to hydrodynamic stability through the Schwarzschild line in a supercritical fluid layer.
abstract: We consider a fluid close to its gas-liquid critical point in a bottom-heated cavity. Due to strong density stratification, both the Schwarzschild and the Rayleigh stability criteria are relevant at the same space scale. Taking advantage of the competition between these two limits of the convection-onset criterion, we numerically exhibit striking non-Boussinesq effects: the reverse transition to stability through the Schwarzschild line of a heat diffusing layer subjected to convection, and the convection onset inside a few-millimeters-thick layer according to the Schwarzschild criterion.
authors.affiliation: MSNM-GP UMR 6181 CNRS, Les Universités Aix-Marseille, IMT-La Jetée, Technopôle de Château Gombert, 38 rue Frédéric Joliot Curie, 13451 Marseille Cedex 20, France.
authors.forename: Gilbert
authors.initials: G
authors.lastname: Accary
authors.forename: Isabelle
authors.initials: I
authors.lastname: Raspo
authors.forename: Patrick
authors.initials: P
authors.lastname: Bontoux
authors.forename: Bernard
authors.initials: B
authors.lastname: Zappoli