High-Rayleigh-Number Convection in a Vertical Channel

Mathieu Gibert (1) , Hervé Pabiou (1) , Francesca Chillà (1) , Bernard Castaing (1)

1 Phys-ENS - Laboratoire de Physique de l'ENS Lyon

We measure the relation between convective heat flux and temperature gradient in a vertical channel filled with water, the average vertical mass flux being zero. Compared to the classical Rayleigh-Bénard case, this situation has the advantage of avoiding plates and, thus, their neighborhood, in which is usually concentrated most of the temperature gradient. Consequently, inertial processes should control the convection, with poor influence of the viscosity. This idea gives a good account of our observations, if we consider that a natural vertical length, different from the channel width, appears. Our results also suggest that heat fluxes can be deduced from velocity measurements in free convective flows. This confers to our results a wide range of applications.

Mots clés: convection; Rayleigh; Bénard; turbulent; heat flux; boundary layer; turbulent convection

Domaines: Dynamique des Fluides [physics.flu-dyn]; Mécanique statistique [cond-mat.stat-mech]; Mécanique des fluides [physics.class-ph]; Géophysique [physics.geo-ph]; Physique Atmosphérique et Océanique [physics.ao-ph]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Mathieu Gibert, Hervé Pabiou, Francesca Chillà, Bernard Castaing. High-Rayleigh-Number Convection in a Vertical Channel. Physical Review Letters, 2006, 96 (8), pp.084501. ⟨10.1103/PhysRevLett.96.084501⟩. ⟨ensl-00000004⟩