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Buoyant convection resulting from dissolution and permeability growth in vertical limestone fractures
Author(s) -
Chaudhuri A.,
Rajaram H.,
Viswanathan H.,
Zyvoloski G.,
Stauffer P.
Publication year - 2009
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 - 10.1029/2008gl036533
Subject(s) - geology , convection , instability , convective instability , rayleigh number , dissolution , mechanics , geothermal gradient , convection cell , permeability (electromagnetism) , petrology , pressure gradient , geophysics , combined forced and natural convection , natural convection , chemistry , physics , biochemistry , oceanography , membrane
Upward flow through vertical fractures in limestone formations under a geothermal gradient favors dissolution and permeability growth. We investigate the transition from conductive and forced convective regimes to instability and buoyant convection as a result of permeability growth. The onset time for instability and roll height at onset depend on the initial aperture and driving pressure. A modified Rayleigh number criterion is proposed, which provides a unified interpretation of the instability across a wide range of initial aperture and driving pressure. Interaction between buoyant convection and aperture alteration leads to narrow upward flow paths supporting dissolution and precipitation in surrounding downward flow regions.