We studied the role of intra-pore eddies, from viscous to inertial flows, in modifying continuum-scale flow inside pores. Flow regimes spanning Reynolds Number Re ∼ 0 to 1350 are divided into three zones - one zone follows Darcy flow, and the other two zones describe non-Darcy or Forchheimer flow. During viscous flows, i.e., Re < 1, stationary eddies occupy about 1/5 of the pore volume. Eddies grow when Re > 1, and their growth leads to the deviation from Darcy's law and the emergence of Forchheimer flow manifested as a characteristic reduction in the apparent hydraulic conductivity Ka. The reduction in Ka is due to the narrowing of the flow channel which is a consequence of the growth in eddies. The two zones of Forchheimer flow correspond to the changes in rate of reduction in Ka, which in turn are due to the changes in eddy growth rate. Since the characteristics of Forchheimer flow are specific to pore geometry, our results partly explain why a variety of Forchheimer models are expected and needed for different porous media.
K. Chaudhary et al., "The Role of Eddies inside Pores in the Transition from Darcy to Forchheimer Flows," Geophysical Research Letters, vol. 38, no. 24, American Geophysical Union (AGU), Dec 2011.
The definitive version is available at https://doi.org/10.1029/2011GL050214
Civil, Architectural and Environmental Engineering
Keywords and Phrases
Porous materials; Darcy flows; Darcy's law; Flow channels; Flow regimes; Forchheimer models; Inertial flow; Pore geometry; Pore volume; Rate of reduction; Reynolds number; Darcy law; Eddy; Hydraulic conductivity; Numerical model; Porous medium; Viscous flow; Volume
International Standard Serial Number (ISSN)
Article - Journal
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