Patterned ground formation and penetrative convection in porous media |
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| Authors: | J H George R D Gunn B Straughan |
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| Institution: | 1. Department of Mathematics , University of Wyoming , Laramie, Wyoming, 82071, U.S.A.;2. Department of Chemical Engineering , University of Wyoming , Laramie, Wyoming, 82071, U.S.A.;3. Department of Mathematics , University of Glasgow , Glasgow, G12 8QW, Scotland |
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| Abstract: | Abstract A theoretical explanation is advanced consisting of a five stage process for the formation of polygonal ground which consists of stone borders forming regular hexagons and soil centres. One of these stages, namely the onset of convection in a porous soil between temperatures of 0°C and approximately 4-6°C, is studied analytically. Darcy's law is employed but variable permeability is allowed for and a parabolic density dependence on temperature is assumed. It is found that the theoretical predictions of the aspect ratio agree very well with field studies when a constant upper surface heat flux condition is imposed and an upwardly stratified permeability is chosen. Field study data, which agree very well with the theory, are reported in detail. |
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| Keywords: | Penetrative convection porous media pattern formation polygonal stone nets |
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