The Forchheimer Approximation allows the user to estimate pressure drop or mean velocities for high Reynolds numbers that present solvers cannot handle yet. It is also possible to change the fluid properties (i.e., viscosity and density) afterwards and estimate pressure drop or mean velocities for other fluids.

Forchheimer’s equation describes the pressure drop of a fluid flow (in a porous media). The equation extends Darcy’s law and considers the pressure drop caused by turbulence in addition to the pressure drop caused by dynamic viscosity.

where (m/s) is the fluid flow velocity, (m2) is the permeability, (Pa ∙ s) is the dynamic viscosity, (Pa) is the pressure, and (kg/m3) is the density.

The new symbol (m) is the non-Darcy permeability coefficient and depends on the porous media only. It does not depend on the flowing fluid.

The Forchheimer Approximation Options dialog is completely different to the others options dialogs. There are no tabs, and all solver parameters are entered directly in the single dialog.

At the top of the dialog, a customized Result File Name (*.gdr) should be entered to differentiate the results of sets of Forchheimer approximations.

The Forchheimer Approximation Options dialog is organized in two panels. Set up the parameters measured in experiments in the Measured Experiment panel and the parameters to use for the simulation in the Predicted Experiment panel.