**Syntax**

` >> PARALLEL PLATE`

**Parent Command**

` > PARAMETER`

**Subcommand**

` >>> MATERIAL`

**Description**

This command selects as a parameter the aperture of a parallel plate fracture model. The single fracture must be modeled as a 1D- or 2D model of thickness 1 meter, i.e., aperture must be identical to porosity. Furthermore, the capillary pressure model must contain a parameter CP(2,NMAT) which represents the gas entry pressure (e.g., Brooks-Corey (ICP=10), van Genuchten (ICP=11)). The parallel plate model relates porosity phi, permeability k [m^{2}], and gas entry pressure p_{e} [Pa] to aperture a [m] as follows:

phi = ak = a^{3}/12

p_{e} = 0.14366/a

Note that using this option overwrites the porosity, absolute permeability and parameter CP(2,NMAT) given in the TOUGH2 input file. Note that the parallel plate model is not consistently applied. Using a relative permeability and capillary pressure function presumes some surface roughness or aperture distribution within the fracture plane.

**Example**

` > PARAMETER
>> aperture in PARALLEL PLATE fracture model
>>> ROCK type : FRACT
>>>> LOGARITHM
>>>> PRIOR information : -4.0 (100 micron)
>>>> standard DEVIATION: 1.0
>>>> RANGE : -5.0 -3.0
<<<<
<<<
<<`

**See Also**

` - `