Unsteady two-dimensional convection in a bottom heated supercritical fluid

Isabelle Raspo (1) , Bernard Zappoli (2) , Patrick Bontoux (1)

1 M2P2 - Modélisation et Simulation Numérique (en mécanique des fluides)
2 CNES - Centre National d'Études Spatiales [Toulouse]

We consider a closed Rayleigh-Bénard cell containing a fluid near its gas-liquid critical point (CP). Due to the divergence of several physical properties near the CP, large Rayleigh numbers can be obtained even for small temperature differences. In the convective regime, the heat flow which is obtained on long time scales exhibits some characteristics of that observed in turbulent convection in normally compressible fluids: it is composed of plumes in thermal boundary layers, jets on lateral walls and a large-scale flow. Our results show that, as it is the case in turbulent convection, this large-scale flow can suddenly change its orientation.

Mots clés: Fluid mechanics; Supercritical fluid; Convective instability; Reversal of large-scale flow

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

Isabelle Raspo, Bernard Zappoli, Patrick Bontoux. Unsteady two-dimensional convection in a bottom heated supercritical fluid. Comptes Rendus Mécanique, 2004, 332 (5-6), pp.353-360. ⟨10.1016/j.crme.2004.02.003⟩. ⟨hal-00838378⟩