TY - JOUR
T1 - The competition between gravity and flow focusing in two-layered porous media
AU - Huppert, Herbert E.
AU - Neufeld, Jerome A.
AU - Strandkvist, Charlotte
PY - 2013/4
Y1 - 2013/4
N2 - The gravitationally driven flow of a dense fluid within a two-layered porous media is examined experimentally and theoretically. We find that in systems with two horizontal layers of differing permeability a competition between gravity driven flow and flow focusing along high-permeability routes can lead to two distinct flow regimes. When the lower layer is more permeable than the upper layer, gravity acts along high-permeability pathways and the flow is enhanced in the lower layer. Alternatively, when the upper layer is more permeable than the lower layer, we find that for a sufficiently small input flux the flow is confined to the lower layer. However, above a critical flux fluid preferentially spreads horizontally within the upper layer before ultimately draining back down into the lower layer. This later regime, in which the fluid overrides the low-permeability lower layer, is important because it enhances the mixing of the two fluids. We show that the critical flux which separates these two regimes can be characterized by a simple power law. Finally, we briefly discuss the relevance of this work to the geological sequestration of carbon dioxide and other industrial and natural flows in porous media.
AB - The gravitationally driven flow of a dense fluid within a two-layered porous media is examined experimentally and theoretically. We find that in systems with two horizontal layers of differing permeability a competition between gravity driven flow and flow focusing along high-permeability routes can lead to two distinct flow regimes. When the lower layer is more permeable than the upper layer, gravity acts along high-permeability pathways and the flow is enhanced in the lower layer. Alternatively, when the upper layer is more permeable than the lower layer, we find that for a sufficiently small input flux the flow is confined to the lower layer. However, above a critical flux fluid preferentially spreads horizontally within the upper layer before ultimately draining back down into the lower layer. This later regime, in which the fluid overrides the low-permeability lower layer, is important because it enhances the mixing of the two fluids. We show that the critical flux which separates these two regimes can be characterized by a simple power law. Finally, we briefly discuss the relevance of this work to the geological sequestration of carbon dioxide and other industrial and natural flows in porous media.
KW - geophysical and geological flows
KW - gravity currents
KW - porous media
UR - http://www.scopus.com/inward/record.url?scp=84875013301&partnerID=8YFLogxK
U2 - 10.1017/jfm.2012.623
DO - 10.1017/jfm.2012.623
M3 - Article (Academic Journal)
AN - SCOPUS:84875013301
SN - 0022-1120
VL - 720
SP - 5
EP - 14
JO - Journal of Fluid Mechanics
JF - Journal of Fluid Mechanics
ER -