diff --git a/applications/solvers/combustion/XiFoam/PDRFoam/StCourantNo.H b/applications/solvers/combustion/XiFoam/PDRFoam/StCourantNo.H
index 65ee2e2b1e..6e175de5b6 100644
--- a/applications/solvers/combustion/XiFoam/PDRFoam/StCourantNo.H
+++ b/applications/solvers/combustion/XiFoam/PDRFoam/StCourantNo.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2021 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -30,21 +30,16 @@ Description
 \*---------------------------------------------------------------------------*/
 
 {
-    scalar meanStCoNum = 0.0;
+    const scalarField sumPhi
+    (
+        fvc::surfaceSum(mag(phiSt))().primitiveField()
+       /rho.primitiveField()
+    );
 
-    if (mesh.nInternalFaces())
-    {
-       scalarField sumPhi
-        (
-            fvc::surfaceSum(mag(phiSt))().primitiveField()
-          / rho.primitiveField()
-        );
+    StCoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();
 
-        StCoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();
-
-        meanStCoNum =
-            0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaTValue();
-    }
+    const scalar meanStCoNum =
+        0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaTValue();
 
     Info<< "St courant Number mean: " << meanStCoNum
         << " max: " << StCoNum << endl;
diff --git a/applications/solvers/compressible/rhoCentralFoam/centralCourantNo.H b/applications/solvers/compressible/rhoCentralFoam/centralCourantNo.H
index 551a1a0175..3b7c1bc745 100644
--- a/applications/solvers/compressible/rhoCentralFoam/centralCourantNo.H
+++ b/applications/solvers/compressible/rhoCentralFoam/centralCourantNo.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2018 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -29,17 +29,16 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-if (mesh.nInternalFaces())
 {
-    scalarField sumAmaxSf(fvc::surfaceSum(amaxSf)().primitiveField());
+    const scalarField sumAmaxSf(fvc::surfaceSum(amaxSf)().primitiveField());
 
     CoNum = 0.5*gMax(sumAmaxSf/mesh.V().field())*runTime.deltaTValue();
 
     meanCoNum =
         0.5*(gSum(sumAmaxSf)/gSum(mesh.V().field()))*runTime.deltaTValue();
+
+    Info<< "Mean and max Courant Numbers = "
+        << meanCoNum << " " << CoNum << endl;
 }
 
-Info<< "Mean and max Courant Numbers = "
-    << meanCoNum << " " << CoNum << endl;
-
 // ************************************************************************* //
diff --git a/applications/solvers/incompressible/shallowWaterFoam/CourantNo.H b/applications/solvers/incompressible/shallowWaterFoam/CourantNo.H
index e165f703b9..d8b64271a6 100644
--- a/applications/solvers/incompressible/shallowWaterFoam/CourantNo.H
+++ b/applications/solvers/incompressible/shallowWaterFoam/CourantNo.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2018 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -29,39 +29,33 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-
-scalar CoNum = 0.0;
-scalar meanCoNum = 0.0;
-scalar waveCoNum = 0.0;
-
-if (mesh.nInternalFaces())
 {
-    scalarField sumPhi
+    const scalarField sumPhi
     (
         fvc::surfaceSum(mag(phi))().primitiveField()
-      / h.primitiveField()
+       /h.primitiveField()
     );
 
-    CoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();
+    const scalar CoNum =
+        0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();
 
-    meanCoNum =
+    const scalar meanCoNum =
         0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaTValue();
 
     // Gravity wave Courant number
-    waveCoNum = 0.25*gMax
+    const scalar waveCoNum = 0.25*gMax
     (
         fvc::surfaceSum
         (
             fvc::interpolate(sqrt(h))*mesh.magSf()
         )().primitiveField()/mesh.V().field()
     )*sqrt(magg).value()*runTime.deltaTValue();
+
+    Info<< "Courant number mean: " << meanCoNum
+        << " max: " << CoNum << endl;
+
+    Info<< "Gravity wave Courant number max: " << waveCoNum
+        << endl;
 }
 
-Info<< "Courant number mean: " << meanCoNum
-    << " max: " << CoNum << endl;
-
-Info<< "Gravity wave Courant number max: " << waveCoNum
-    << endl;
-
-
 // ************************************************************************* //
diff --git a/applications/solvers/lagrangian/denseParticleFoam/CourantNo.H b/applications/solvers/lagrangian/denseParticleFoam/CourantNo.H
index f0ef70106c..63c2e2bb63 100644
--- a/applications/solvers/lagrangian/denseParticleFoam/CourantNo.H
+++ b/applications/solvers/lagrangian/denseParticleFoam/CourantNo.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2013-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2013-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -29,23 +29,18 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-scalar CoNum = 0.0;
-scalar meanCoNum = 0.0;
+scalar CoNum = 0;
 
-if (mesh.nInternalFaces())
 {
-    scalarField sumPhi
-    (
-        fvc::surfaceSum(mag(phic))().primitiveField()
-    );
+    const scalarField sumPhi(fvc::surfaceSum(mag(phic))().primitiveField());
 
     CoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();
 
-    meanCoNum =
+    const scalar meanCoNum =
         0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaTValue();
+
+    Info<< "Courant Number mean: " << meanCoNum
+        << " max: " << CoNum << endl;
 }
 
-Info<< "Courant Number mean: " << meanCoNum
-    << " max: " << CoNum << endl;
-
 // ************************************************************************* //
diff --git a/applications/solvers/multiphase/cavitatingFoam/CourantNo.H b/applications/solvers/multiphase/cavitatingFoam/CourantNo.H
index 8704d02b16..deeec2c66a 100644
--- a/applications/solvers/multiphase/cavitatingFoam/CourantNo.H
+++ b/applications/solvers/multiphase/cavitatingFoam/CourantNo.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2018 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -29,20 +29,15 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-scalar CoNum = 0.0;
-scalar meanCoNum = 0.0;
-scalar acousticCoNum = 0.0;
+scalar CoNum = 0;
+scalar acousticCoNum = 0;
 
-if (mesh.nInternalFaces())
 {
-    scalarField sumPhi
-    (
-        fvc::surfaceSum(mag(phi))().primitiveField()
-    );
+    const scalarField sumPhi(fvc::surfaceSum(mag(phi))().primitiveField());
 
     CoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();
 
-    meanCoNum =
+    const scalar meanCoNum =
         0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaTValue();
 
     acousticCoNum = 0.5*gMax
@@ -52,11 +47,11 @@ if (mesh.nInternalFaces())
             fvc::interpolate(scalar(1)/sqrt(psi))*mesh.magSf()
         )().primitiveField()/mesh.V().field()
     )*runTime.deltaTValue();
+
+    Info<< "phi Courant Number mean: " << meanCoNum
+        << " max: " << CoNum
+        << " acoustic max: " << acousticCoNum
+        << endl;
 }
 
-Info<< "phi Courant Number mean: " << meanCoNum
-    << " max: " << CoNum
-    << " acoustic max: " << acousticCoNum
-    << endl;
-
 // ************************************************************************* //
diff --git a/src/twoPhaseModels/twoPhaseMixture/VoF/alphaCourantNo.H b/src/twoPhaseModels/twoPhaseMixture/VoF/alphaCourantNo.H
index 95bb0a3682..cf0ae763a1 100644
--- a/src/twoPhaseModels/twoPhaseMixture/VoF/alphaCourantNo.H
+++ b/src/twoPhaseModels/twoPhaseMixture/VoF/alphaCourantNo.H
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     | Website:  https://openfoam.org
-    \\  /    A nd           | Copyright (C) 2011-2020 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2022 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -29,17 +29,10 @@ Description
 
 \*---------------------------------------------------------------------------*/
 
-scalar maxAlphaCo
-(
-    runTime.controlDict().lookup<scalar>("maxAlphaCo")
-);
+scalar alphaCoNum = 0;
 
-scalar alphaCoNum = 0.0;
-scalar meanAlphaCoNum = 0.0;
-
-if (mesh.nInternalFaces())
 {
-    scalarField sumPhi
+    const scalarField sumPhi
     (
         mixture.nearInterface()().primitiveField()
        *fvc::surfaceSum(mag(phi))().primitiveField()
@@ -47,11 +40,11 @@ if (mesh.nInternalFaces())
 
     alphaCoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();
 
-    meanAlphaCoNum =
+    const scalar meanAlphaCoNum =
         0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaTValue();
+
+    Info<< "Interface Courant Number mean: " << meanAlphaCoNum
+        << " max: " << alphaCoNum << endl;
 }
 
-Info<< "Interface Courant Number mean: " << meanAlphaCoNum
-    << " max: " << alphaCoNum << endl;
-
 // ************************************************************************* //
diff --git a/src/twoPhaseModels/twoPhaseMixture/VoF/setDeltaT.H b/src/twoPhaseModels/twoPhaseMixture/VoF/setDeltaT.H
index 4ec4138744..31e1d2ff9b 100644
--- a/src/twoPhaseModels/twoPhaseMixture/VoF/setDeltaT.H
+++ b/src/twoPhaseModels/twoPhaseMixture/VoF/setDeltaT.H
@@ -33,6 +33,11 @@ Description
 
 if (adjustTimeStep)
 {
+    const scalar maxAlphaCo
+    (
+        runTime.controlDict().lookup<scalar>("maxAlphaCo")
+    );
+
     scalar deltaT = 1.2*runTime.deltaTValue();
 
     if (CoNum > small)