Fracture
Use this node to model mass transport along thin fractures in porous media. The node assumes that the transport in the tangential direction along the fracture is dominant, as a result of lower flow resistance.
This feature is only available in a limited set of add-on products. See https://www.comsol.com/products/specifications/ for more details on availability.
Fracture Properties
Specify a value for the Fracture thickness dfr.
Matrix Properties
Use the Porous material list to define a material specifying the matrix properties on the current selection. By default the Boundary material is used.
Specify the Porosity, εp (dimensionless) of the porous matrix. This is by default taken From material. Select User defined to instead enter a different value.
Convection
Select an option from the Velocity field list to specify the convective velocity along the fracture. For a consistent model, use a Fracture Flow feature in a Darcy’s Law interface to compute the fluid flow velocity in the fracture.
For User defined, enter values or expressions for the velocity components in the table shown.
The settings for the Diffusion is the similar to the settings for the diffusion coefficients in the Fluid node. The Dispersion settings are identical to the ones in the Dispersion node.