ICP=3 TRUST capillary pressure

TRUST capillary pressure (Narasimhan et al., 1978)

$P_{cap}\quad=\quad\left\{\begin{matrix}-P_e-P_0\left[\frac{1-S_l}{S_l-S_{lr}}\right]^\frac{1}{\eta}&\mathrm{for}\;\ S_l<1\\0&\mathrm{for}\;\ S_l<1\\\end{matrix}\right.$

where

$P_0$ = CP(1) $S_{lr}$= CP(2) $\eta$= CP(3) $P_e$ = CP(4)

Restrictions: CP(2) ≥ 0; CP(3) ≠ 0