From 61c87b555270e0e9545daba33a1700f857045daa Mon Sep 17 00:00:00 2001
From: Johan Roenby <johan.roenby@gmail.com>
Date: Tue, 30 Apr 2019 16:07:48 +0200
Subject: [PATCH] Introduced changes required to make isoAdvector and
 interIsoFoam work with morphing meshes: 1) In the alphaEqn.H U is made
 relative to mesh motion before the interface advection step, 2) in
 isoAdvection::advect() alpha must be multiplied by Vsc0()/Vsc().
 Implementation tested and verified with 1) a spherical interface in a cubic
 domain with no flow, where the domain walls are squeezed together and 2) a
 spherical interfacee inside the sloshingCylinder, again with no flow, so the
 sphere should stay spherical, which it does.

---
 .../solvers/multiphase/interIsoFoam/alphaEqn.H      | 13 +++++++++++++
 .../isoAdvection/isoAdvection/isoAdvection.C        |  8 +++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/applications/solvers/multiphase/interIsoFoam/alphaEqn.H b/applications/solvers/multiphase/interIsoFoam/alphaEqn.H
index fda7a30c9b..8de0ac0161 100644
--- a/applications/solvers/multiphase/interIsoFoam/alphaEqn.H
+++ b/applications/solvers/multiphase/interIsoFoam/alphaEqn.H
@@ -1,6 +1,19 @@
 {
+    // Temporarily making U relative to mesh motion
+    if (mesh.moving())
+    {
+        U -= fvc::reconstruct(mesh.phi());
+    }
+
     // Updating alpha1
     advector.advect();
+
+    // Making U absolute again after advection step
+    if (mesh.moving())
+    {
+        U += fvc::reconstruct(mesh.phi());
+    }
+
     #include "rhofs.H"
     rhoPhi = advector.getRhoPhi(rho1f, rho2f);
 
diff --git a/src/finiteVolume/fvMatrices/solvers/isoAdvection/isoAdvection/isoAdvection.C b/src/finiteVolume/fvMatrices/solvers/isoAdvection/isoAdvection/isoAdvection.C
index ac7667e663..edb2d75f1c 100644
--- a/src/finiteVolume/fvMatrices/solvers/isoAdvection/isoAdvection/isoAdvection.C
+++ b/src/finiteVolume/fvMatrices/solvers/isoAdvection/isoAdvection/isoAdvection.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                 isoAdvector | Copyright (C) 2016-2017 DHI
-              Modified work | Copyright (C) 2018 Johan Roenby
+              Modified work | Copyright (C) 2019 Johan Roenby
 -------------------------------------------------------------------------------
 
 License
@@ -852,6 +852,12 @@ void Foam::isoAdvection::advect()
     // Do the isoAdvection on surface cells
     timeIntegratedFlux();
 
+    // Adjust alpha for mesh motion
+    if (mesh_.moving())
+    {
+        alpha1In_ *= (mesh_.Vsc0()/mesh_.Vsc());
+    }
+
     // Adjust dVf for unbounded cells
     limitFluxes();