From 05435219926f43ab42f36144d064e4196ea05f3f Mon Sep 17 00:00:00 2001
From: Will Bainbridge <http://cfd.direct>
Date: Fri, 27 Jan 2023 13:18:06 +0000
Subject: [PATCH] solver: Make time-step fractional increase available
 externally

---
 applications/solvers/foamMultiRun/setDeltaT.C | 9 ++++++++-
 applications/solvers/foamRun/setDeltaT.C      | 9 ++++++++-
 src/finiteVolume/solver/solver.C              | 3 +++
 src/finiteVolume/solver/solver.H              | 6 ++++++
 4 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/applications/solvers/foamMultiRun/setDeltaT.C b/applications/solvers/foamMultiRun/setDeltaT.C
index ff1a79e684..045affd17d 100644
--- a/applications/solvers/foamMultiRun/setDeltaT.C
+++ b/applications/solvers/foamMultiRun/setDeltaT.C
@@ -74,7 +74,14 @@ void Foam::adjustDeltaT(Time& runTime, const PtrList<solver>& solvers)
 
         if (transient && deltaT < rootVGreat)
         {
-            runTime.setDeltaT(min(1.2*runTime.deltaTValue(), deltaT));
+            runTime.setDeltaT
+            (
+                min
+                (
+                    solver::maxIncreaseDeltaT*runTime.deltaTValue(),
+                    deltaT
+                )
+            );
             Info<< "deltaT = " <<  runTime.deltaTValue() << endl;
         }
     }
diff --git a/applications/solvers/foamRun/setDeltaT.C b/applications/solvers/foamRun/setDeltaT.C
index 7960fe8fb0..34da064084 100644
--- a/applications/solvers/foamRun/setDeltaT.C
+++ b/applications/solvers/foamRun/setDeltaT.C
@@ -52,7 +52,14 @@ void Foam::adjustDeltaT(Time& runTime, const solver& solver)
      && solver.maxDeltaT() < rootVGreat
     )
     {
-        runTime.setDeltaT(min(1.2*runTime.deltaTValue(), solver.maxDeltaT()));
+        runTime.setDeltaT
+        (
+            min
+            (
+                solver::maxIncreaseDeltaT*runTime.deltaTValue(),
+                solver.maxDeltaT()
+            )
+        );
         Info<< "deltaT = " <<  runTime.deltaTValue() << endl;
     }
 }
diff --git a/src/finiteVolume/solver/solver.C b/src/finiteVolume/solver/solver.C
index c881f9b3f5..944dd3f719 100644
--- a/src/finiteVolume/solver/solver.C
+++ b/src/finiteVolume/solver/solver.C
@@ -35,6 +35,9 @@ namespace Foam
 }
 
 
+const Foam::scalar Foam::solver::maxIncreaseDeltaT = 1.2;
+
+
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
 bool Foam::solver::writeData(Ostream&) const
diff --git a/src/finiteVolume/solver/solver.H b/src/finiteVolume/solver/solver.H
index a0acb6492c..d45c4b233d 100644
--- a/src/finiteVolume/solver/solver.H
+++ b/src/finiteVolume/solver/solver.H
@@ -76,6 +76,12 @@ public:
         bool LTS;
 
 
+    // Public Static Data
+
+        //- Maximum fractional increase in deltaT
+        static const scalar maxIncreaseDeltaT;
+
+
 private:
 
     // Private Member Data