Description
Permeability is part of the proportionality constant in Darcy's law which relates discharge (flow rate) and fluid physical properties (e.g. viscosity), to a pressure gradient applied to the porous media:
Therefore:
where:
- is the superficial fluid flow velocity through the medium (i.e., the average velocity calculated as if the fluid were the only phase present in the porous medium) (m/s)
- is the permeability of a medium (m2)
- is the dynamic viscosity of the fluid (Pa·s)
- is the applied pressure difference (Pa)
- is the thickness of the bed of the porous medium (m)
In naturally occurring materials, permeability values range over many orders of magnitude (see table below for an example of this range).
Read more about this topic: Permeability (earth Sciences)
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