Electroosmotic phenomena in fractures

Electroosmotic phenomena in fractures have been investigated in the linear limit for various double-layer thicknesses. The effects of the geometrical parameters were systematically studied for deterministic sinusoidal and ran dom self-affine fractures. The numerical results show a definite influence of the surface amplitude on electroosmotic processes. For self-affine fract ures, the roughness or Hurst exponent has a much larger incidence than the correlation parameter between the two surfaces. All the electroosmotic coup ling coefficients can be gathered in a single relationship which depends on a characteristic length scale Lambda, applicable to every configuration. S uch a length was already found useful for porous media, but the relationshi p is different. (C) 2000 Academic Press.