Numerical studies of thermal convection with temperature-and pressure-dependent viscosity at extreme viscosity contrasts
2015 (English)In: Physics of fluids, ISSN 1070-6631, E-ISSN 1089-7666, Vol. 27, no 7, 076603Article in journal (Refereed) Published
Motivated by convection of planetary mantles, we consider a mathematical model for Rayleigh-Benard convection in a basally heated layer of a fluid whose viscosity depends strongly on temperature and pressure, defined in an Arrhenius form. The model is solved numerically for extremely large viscosity variations across a unit aspect ratio cell, and steady solutions for temperature, isotherms, and streamlines are obtained. To improve the efficiency of numerical computation, we introduce a modified viscosity law with a low temperature cutoff. We demonstrate that this simplification results in markedly improved numerical convergence without compromising accuracy. Continued numerical experiments suggest that narrow cells are preferred at extreme viscosity contrasts, and this conclusion is supported by a linear stability analysis.
Place, publisher, year, edition, pages
2015. Vol. 27, no 7, 076603
Mechanical Engineering Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-172722DOI: 10.1063/1.4923061ISI: 000358872200043ScopusID: 2-s2.0-84937010951OAI: oai:DiVA.org:kth-172722DiVA: diva2:849459
QC 201508282015-08-282015-08-272015-08-28Bibliographically approved