Mechanisms of the onset of Rayleigh-Benard instabilities for a near critical fluid

• Published in: Advances in space research Vol. 22; no. 8; pp. 1249 - 1252
• Main Authors: Larroudé, P., Amiroudine, S., Bontoux, P., Zappoli, B.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-1998
• ISSN: 0273-1177; 1879-1948
• DOI: 10.1016/S0273-1177(98)80031-8

Phenomena in near critical fluids has recently led to important theoretical and experimental results, in particular the prediction and the evidence of a mode of heat equilibration called the Piston Effect (PE). The numerical method uses a finite volume approximation based on the SIMPLER algorithm and it considers an acoustic filtering on the Piston-Effect time-scale. In the case of a Rayleigh-Bénard configuration (heated from below). different types of flows are shown to develop depending on the local Rayleigh numbers and on the proximity with the critical point. The types of flows at larger Rayleigh numbers than critical, exhibit plumes at the bottom while the cooled top layer gives rise to an unstable diffusive layer.