From c10085b4689a1f705c369ad89e1fc5745fc9b5d4 Mon Sep 17 00:00:00 2001
From: Bo Gao <83304414+gaobhub@users.noreply.github.com>
Date: Mon, 10 Jul 2023 16:13:02 -0400
Subject: [PATCH] add new relperm equations for documentation

---
 .../constitutive_relations/wrm/rel_perm_frzBC_evaluator.hh     | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/pks/flow/constitutive_relations/wrm/rel_perm_frzBC_evaluator.hh b/src/pks/flow/constitutive_relations/wrm/rel_perm_frzBC_evaluator.hh
index 09e4d620a..9c6927647 100644
--- a/src/pks/flow/constitutive_relations/wrm/rel_perm_frzBC_evaluator.hh
+++ b/src/pks/flow/constitutive_relations/wrm/rel_perm_frzBC_evaluator.hh
@@ -19,7 +19,8 @@ Agnihotri et al. (2023) for discussions about the influence of relative permeabi
 model on discharge under freezing conditions.
 
 .. math::
-   k_{rel} = .... \omega
+   k_{rel} = ( 1 - F_{frz} ) \times ( \frac{1 - s_{g} - s_r}{1 - s_r} )^{2*b + 3} \\
+   F_{frz} = \mathrm{exp}( -\omega \times ( s_{l} + s_{g} ) ) - \mathrm{exp}( -\omega )
 
 Note this implementation is currently a bit inconsistent in that it uses WRMs
 to get the residual saturation, and uses a global value for b, the Clapp and