Convection in a vertical channel

Jean-Christophe Tisserand (1, 2) , Mathieu Creyssels (3) , Mathieu Gibert (2) , Bernard Castaing (2) , Francesca Chillà (2)

1 ENS de Lyon - École normale supérieure de Lyon
2 Phys-ENS - Laboratoire de Physique de l'ENS Lyon
3 LMFA - Laboratoire de Mecanique des Fluides et d'Acoustique

The flow generated by heat convection in a long, vertical channel is studied by means of particle imagery velocimetry techniques, with the help of the thermal measurements from a previous paper (Gibert et al 2009 Phys. Fluids 21 035109). We analyse the mean velocity profiles and the Reynolds stresses, and compare the present results with the previous ones obtained in a larger cell and at a larger Reynolds number.We calculate the horizontal temperature profile and the related horizontal heat flux. The pertinence of effective turbulent diffusivity and viscosity is confirmed by the low value of the associated mixing length. We study the one-point and two-point statistics of both velocity components. We show how the concept of turbulent viscosity explains the relations between the local probability density functions (pdf) of fluctuations for temperature, vertical and horizontal velocity components. Despite the low Reynolds number values explored, some conclusions can be drawn about the small scale velocity differences and the related energy cascade.

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

Jean-Christophe Tisserand, Mathieu Creyssels, Mathieu Gibert, Bernard Castaing, Francesca Chillà. Convection in a vertical channel. New Journal of Physics, 2010, 12, pp.075024. ⟨10.1088/1367-2630/12/7/075024⟩. ⟨hal-00566067⟩