https://doi.org/10.1140/epjb/e2005-00211-7
Scaling in convective evaporation and sidewall boundary layer
Laboratoire Hydrogéochimie et Études de sites, Commissariat à
l'Énergie Atomique, B.P. 12, 91680 Bruyères-le-Châtel, France
Corresponding author: a perrier@ipgp.jussieu.fr
Received:
23
November
2004
Revised:
8
March
2005
Published online:
13
July
2005
Turbulent convection at aspect ratios from 0.06 to 2 is
investigated in the laboratory with evaporation experiments from vertical
cylinders having different diameters and liquid levels. With alcohol, only
diffusive evaporation takes place. With water, for small diameters,
evaporation proceeds by diffusion whereas convective evaporation develops
when the diameter is increased. This onset can be effectively interpreted in
terms of a viscous sidewall boundary layer, whose thickness δ varies with
respect to the available height h according to δ/h = 3.4 Ra
versus Rayleigh number Ra. The Sherwood number Sh, analog of the Nusselt
number, exhibits a power law variation Sh = 0.6 Ra
for Ra
varying from 104 to
. The scaling observed in this case of an
open boundary is thus similar to the scaling measured in confined
Rayleigh-Bénard convection.
PACS: 92.60.Jq – Water in the atmosphere (humidity, clouds, evaporation, precipitation) / 47.27.-i – Turbulent flows, convection, and heat transfer / 47.27.Sd – Noise (turbulence generated) / 92.60.Ek – Convection, turbulence, and diffusion
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2005