Natural convection in porous media: Effect of weak dispersion on bifurcation

Xiaowei S. He, John G. Georgiadis

Research output: Contribution to journalArticlepeer-review


We use weakly nonlinear analysis via a two-parameter expansion to study bifurcation of conduction into cellular convection of an internally heated fluid in a porous medium that forms a horizontal layer between two isothermal walls. The Darcy-Boussinesq model of convection is enhanced by including two nonlinear terms: (i) quadratic (Forcheimer) drag; and (ii) hydrodynamic dispersion enhancement of the thermal conductivity described by a weak linear relationship between effective conductivity and local amplitude of filtration velocity. The impact of the second term on the shape of the bifurcation curve for two-dimensional rolls is profound in the presence of uniform volumetric heating. The resulting bifurcation structure is unlike any pitchfork bifurcations typical of the classical Benard problem. Although direct experimental validation of the novel bifurcation is not available, we would like to register it as an alternative or a supplement to models of small imperfections, and as an attempt to account for the scatter of observed critical values for the first bifurcation.

Original languageEnglish (US)
Pages (from-to)285-298
Number of pages14
JournalJournal of Fluid Mechanics
StatePublished - Jul 1990
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Applied Mathematics


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