### MICHAEL MANGA: Recent Refereed Publications

## Abstracts

#### Manga, M., D. Weeraratne, and S.J.S. Morris, Boundary-layer thickness
in Benard convection of a liquid with a temperature-dependent viscosity

Abstract:

The interior temperature T_i of a fluid
undergoing thermal convection at high Rayleigh numbers reflects
the heat flux through both boundaries, and thus
the relative thickness of thermal boundary layers. For constant-viscosity convection, T_i is the mean of the boundary temperatures.
If viscosity \mu decreases with increasing temperature T, however,
convection occurs beneath a stagnant layer and T_i increases
relative to the isoviscous case. We show that the predictions of
T_i by boundary layer
models for both small and large viscosity variations
agree with published experimental data in the appropriate limits.
Of particular interest to applications involving asymptotically
large viscosity variations, is the result
that the temperature difference across the
hot thermal boundary layer is proportional to the rheological
temperature scale -1/(d log \mu/dT).
Experimental data indicate that
T_i does not depend on the Rayleigh number or
Reynolds number, at least for Re < O(100).

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