IRP=10 Modified Brooks-Corey Model

IRP = 10 Modified Brooks-Corey Model

A modified version of the Brooks-Corey model (Luckner et al., 1989) has been implemented to prevent the capillary pressure from decreasing towards negative infinity as the effective saturation approaches zero. The modified Brooks-Corey model is invoked by setting both IRP and ICP to 10.

${{k}_{rl}}={{S}_{ek}}^{\frac{2+3\lambda }{\lambda }}$

${{k}_{rg}}=\left\{ \begin{matrix} {{\left( 1-{{S}_{ek}} \right)}^{2}}\left( 1-{{S}_{ek}}^{\frac{2+\lambda }{\lambda }} \right)\text{ if RP(3) }=\text{ 0} \\ 1-{{k}_{rl}}\text{ if RP(3) }\ne \text{ 0} \\ \end{matrix} \right.$

where

${S_{ek}} = \frac{{{S_l} - {S_{lrk}}}}{{1 - {S_{lrk}} - {S_{gr}}}}$

Parameters: RP(1) = ${S_{lrk}}$

RP(2) = ${S_{gr}}$

RP(3) = flag to indicate which equation is used for $k_{rg}$