[Convection bidimensionnelle instationnaire dans un fluide supercritique chauffé par le bas]
On considère un fluide proche de son point critique liquide–gaz (PC) dans une cellule de Rayleigh–Bénard fermée. Du fait de la divergence de plusieurs propriétés physiques au voisinage du PC, des nombres de Rayleigh importants peuvent être obtenus pour de faibles différences de températures. Dans le régime convectif, le champ thermique obtenu sur les longues échelles de temps présente certaines caractéristiques de celui observé en convection turbulente dans un fluide normalement compressible : il est composé de panaches issus des couches limites thermiques, de jets le long des parois latérales et d'un écoulement à grande échelle. Nos résultats montrent que, comme en convection turbulente, cet écoulement peut soudain changer d'orientation.
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.
Mot clés : Mécanique des fluides, Fluide supercritique, Instabilité convective, Changement d'orientation de l'écoulement à grande échelle
@article{CRMECA_2004__332_5-6_353_0,
author = {Isabelle Raspo and Bernard Zappoli and Patrick Bontoux},
title = {Unsteady two-dimensional convection in a bottom heated supercritical fluid},
journal = {Comptes Rendus. M\'ecanique},
pages = {353--360},
publisher = {Elsevier},
volume = {332},
number = {5-6},
year = {2004},
doi = {10.1016/j.crme.2004.02.003},
language = {en},
}
TY - JOUR AU - Isabelle Raspo AU - Bernard Zappoli AU - Patrick Bontoux TI - Unsteady two-dimensional convection in a bottom heated supercritical fluid JO - Comptes Rendus. Mécanique PY - 2004 SP - 353 EP - 360 VL - 332 IS - 5-6 PB - Elsevier DO - 10.1016/j.crme.2004.02.003 LA - en ID - CRMECA_2004__332_5-6_353_0 ER -
Isabelle Raspo; Bernard Zappoli; Patrick Bontoux. Unsteady two-dimensional convection in a bottom heated supercritical fluid. Comptes Rendus. Mécanique, Volume 332 (2004) no. 5-6, pp. 353-360. doi : 10.1016/j.crme.2004.02.003. https://comptes-rendus.academie-sciences.fr/mecanique/articles/10.1016/j.crme.2004.02.003/
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