# HydroGeoSphere/Tabular Constitutive Relationships

The instructions described here can be used to modify the default variably-saturated properties for a porous medium, discrete fracture or dual continuum. Before issuing them it is necessary to choose which type of medium they should be applied to, as discussed in Section 5.8.1.

For each instruction we will again indicate its scope (i.e. .grok, .mprops, .dprops, .fprops). Recall that if an instruction is used in the prefix.grok file, it will affect the current set of chosen zones, while in a properties (e.g. .mprops) file, it will only affect the named material of which it is a part.

## Unsaturated tables

Scope: .grok .mprops .fprops .dprops

Causes grok to use tables to describe the constitutive relationships for the medium and to begin reading a group of instructions that define the tables until it encounters an End instruction.

If no further instructions are issued, the default tabular parameter values given in Table 5.12, Table 5.14 and Table 5.17 will be used for porous media, discrete fractures and dual continua respectively.

In the case of porous and dual media, this instruction overrides the pseudo-soil default so that relative permeability factors are applied to both horizontal and vertical flow.

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The following instructions can be used to modify the default tables which define the constitutive relationships:

## Pressure-saturation

Scope: .grok .mprops .fprops .dprops

1. pressure(1), saturation(1) First entry.
2. pressure(2), saturation(2) Second entry.
...etc.
n. pressure(n), saturation(n) nth entry.
n+1. end The string 'end'

Paired values of pressure ${\displaystyle {\psi }}$  and saturation ${\displaystyle S}$  should be entered from lowest pressure (i.e. most negative) to highest pressure, usually zero. The last line of the table must be an end card, and the number of entries in the list are counted automatically to determine the table size.

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## Saturation-relative k

Scope: .grok .mprops .fprops .dprops

1. saturation(1), relative permeability(1) First entry.
2. saturation(2), relative permeability(2) Second entry.
...etc.
n. saturation(n), relative permeability(n) nth entry.
n+1. end The string 'end'

Paired values of saturation ${\displaystyle S}$  and relative permeability ${\displaystyle k_{rw}}$  should be entered from lowest to highest saturation. The last line of the table must be an end card, and the number of entries in the list are counted automatically to determine the table size.

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