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SUMMARY:Reactive-infiltration instabilities in fractures and porous rock -
  Szymczak\, P (Uniwersytet Warszawski)
DTSTART:20120821T103000Z
DTEND:20120821T113000Z
UID:TALK39290@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:A reactive fluid flowing through a porous or fractured rock an
 d dissolving the rock matrix may trigger an instability\, leading to spont
 aneous formation of pronounced channels or wormholes. I will present a lin
 ear-stability analysis of this system and show that there are two differen
 t instabilites. One is associated with an initial uniform-porosity state a
 nd the other with a steadily propagating one-dimensional dissolution front
 . I will discuss the origin of both instabilities and the physical conditi
 ons under which they can be observed. In particular\, it is argued that th
 e former 'initial- state' instability is relevant to the dissolution of fr
 actures in carbonate rocks\, giving rise to the formation of limestone cav
 es. Finally\, I will discuss the later stages of the system evolution\, wh
 en the channels interact\, competing for the available flow\; eventually t
 he growth of the shorter ones ceases. This leads to self-similar patterns 
 of growth\, with the flow becoming concentrated within a few active channe
 ls.\n
LOCATION:Seminar Room 1\, Newton Institute Gatehouse
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