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18.104.22.168 Constant Isotropic Diffusivity
The material type for constant isotropic diffusivity materials is “diff-const-iso”. The following material parameters must be defined:
|<free_diff>||free diffusivity of solute (diffusivity in solution)||[L /t]|
|<diff>||constant isotropic diffusivity of solute in biphasic-solute mixture||[L /t]|
When the permeability is isotropic, For this material model, is constant. This assumption is only true when strains are small. Note that the user must specify , since a solute cannot diffuse through the biphasic-solute mixture faster than in free solution.
<diffusivity name="Permeability" type="diff-const-iso"> <free_diff>1e-9</ free_diff > <diff>0.5e-9</diff> </diffusivity>