Gas Phase Darcy Velocity in Porous Media#

Gas phase Darcy velocity in porous media = {yes | no}


Description / Usage#

This post-processing option will lead to the explicit calculation and storage of the Darcy velocity components in the gas phase, viz. the velocity of the gas phase due to gas-phase pressure gradients. This option is only available for POROUS_TWO_PHASE media types (cf. Media Type card). The velocity components appear in the output EXODUS II file as the nodal variables Darcy_Vel_g_0, Darcy_Vel_g_1 and Darcy_Vel_g_2.

The permissible values for this postprocessing option are:

 yes Calculate the gas-phase Darcy velocity components and write to the output EXODUSII file. no Do not calculate the gas phase velocity components.

Examples#

This input example turns on calculation of the gas phase velocity components:

Gas phase Darcy velocity in porous media =yes


Technical Discussion#

The gas-phase Darcy velocity is given by the extended Darcy law, which accounts for the relative reduced flow due to the presence of another phase, viz.

Here $$\nu_g$$ represents the Darcy flux, or Darcy velocity, in the gas phase, k is the permeability of the porous medium, $$k_g$$ is the relative permeabilities for the gas and liquid phases respectively, $$\mu_g$$ are the gas viscosity, $$p_g$$ is the pressure in the gas phase, and g is the gravitational force vector. $$\rho_g$$ is the density of the gas phase and is equal to the sum of the partial densities of air and solvent vapor,

References#

GT-009.3: GOMA’s Capabilities for Partially Saturated Flow in Porous Media, September 1, 2002, P. R. Schunk