Effective Diffusivity in Porous Media

Written by Jerry Ratzlaff on . Posted in Geotechnical Engineering

partially saturated soil 4Effective diffusivity in porous media, abbreviated as \( D_e \), is the adequate dispersion of gas or liguid through the voids of soil.


Effective diffusivity in porous media formula

\(\large{ D_e =  \frac{ D \; n \; \delta }{ \tau }  }\)   


 Units English Metric
\(\large{ D_e } \) = effective diffusivity \(\large{ \frac{ft^2}{sec} }\) \(\large{ \frac{m^2}{s} }\)
\(\large{ D } \) = diffusion coefficient in gas or liquid filling the pores \(\large{\frac{ft^2}{sec}}\) \(\large{\frac{m^2}{s}}\)
\(\large{ n }\) = porosity available for transportation \(\large{dimensionless}\)
\(\large{ \delta }\)  (Greek symbol delta) = constrictivity \(\large{dimensionless}\)
\(\large{ \tau } \)  (Greek symbol tau) = tortuosity \(\large{dimensionless}\)


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Tags: Soil Equations Geotechnical Equations Diffusion Equations