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Onset of convection with temperature‐ and depth‐dependent viscosity
Author(s) -
Korenaga Jun,
Jordan Thomas H.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl015672
Subject(s) - buoyancy , viscosity , scaling , compressibility , convection , thermodynamics , rayleigh number , mechanics , scaling law , physics , gaussian , statistical physics , natural convection , mathematics , geometry , quantum mechanics
We derive a scaling law for the onset of convection in an incompressible fluid cooled from above with temperature‐ and depth‐dependent viscosity, on the basis of 2‐D numerical simulation. Rayleigh numbers up to 10 7 are considered. The activation energy is varied from 0 to 200 kJ mol −1 , and a variation of up to 10 3 is considered in depth‐dependent reference viscosity. Our scaling law is shown to be able to handle a variety of buoyancy distributions, including highly non‐Gaussian and multimodal distributions, with a tightly constrained critical Rayleigh number.