Effect of viscosity, capillarity and grid spacing on thermal variable-density flow

Thomas Graf, Michel C. Boufadel

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

The HydroGeoSphere model is further developed and used to investigate the effects of viscosity, capillarity and grid spacing on thermal variable-density flow. Under saturated and unsaturated flow conditions, the flow dynamics significantly depends on the viscosity assumption (constant vs. variable), where downwelling regions (constant viscosity) become upwelling regions (temperature-dependent variable viscosity). Capillarity does not change the location of downwelling and upwelling regions. Capillarity can significantly alter the flow dynamics in the way that the water table acts as a " lid" to flow, and it diverts a thermal plume laterally. Significance of capillarity increases with increasing soil moisture. Thermal convective flow is highly sensitive to spatial discretization. While the flow dynamics remains to be a function of grid level, spatial discretization Δ. x=Δ z= 1 m appears to be appropriate to simulate unsaturated variable-density flow and heat transfer in porous media because estimated errors have asymptotically reached a minimum.

Original languageEnglish (US)
Pages (from-to)41-57
Number of pages17
JournalJournal of Hydrology
Volume400
Issue number1-2
DOIs
StatePublished - Mar 30 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Water Science and Technology

Keywords

  • Capillarity
  • Density
  • Elder problem
  • Heat flow
  • Unsaturated
  • Viscosity

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