From 4c68b4bf5b5a809d2c9e41b2123f3bc89a1f0e40 Mon Sep 17 00:00:00 2001
From: Henry Weller <http://cfd.direct>
Date: Sat, 29 Apr 2023 21:42:34 +0100
Subject: [PATCH] multiphaseEuler/interfacialModels/dragModels/Ergun: Reverted
 handling of the continuous phase-fraction

back to the form in the original multiphaseEulerFoam, i.e. using the dispersed
phase-fraction directly rather than 1 - continuous phase fraction.
---
 .../interfacialModels/dragModels/Ergun/Ergun.C             | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/applications/solvers/modules/multiphaseEuler/interfacialModels/dragModels/Ergun/Ergun.C b/applications/solvers/modules/multiphaseEuler/interfacialModels/dragModels/Ergun/Ergun.C
index 175a9f17e0..9a67ee81f3 100644
--- a/applications/solvers/modules/multiphaseEuler/interfacialModels/dragModels/Ergun/Ergun.C
+++ b/applications/solvers/modules/multiphaseEuler/interfacialModels/dragModels/Ergun/Ergun.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2023 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -68,10 +68,9 @@ Foam::tmp<Foam::volScalarField> Foam::dragModels::Ergun::CdRe() const
         (4.0/3.0)
        *(
             150
-           *max(1 - continuous, dispersed.residualAlpha())
+           *max(dispersed, dispersed.residualAlpha())
            /max(continuous, continuous.residualAlpha())
-          + 1.75
-           *interface_.Re()
+          + 1.75*interface_.Re()
         );
 }