From a2a74cbb7921c2e0de3e5aa1f319e5913b65e771 Mon Sep 17 00:00:00 2001
From: Henry Weller <http://openfoam.org>
Date: Tue, 8 Oct 2019 16:14:38 +0100
Subject: [PATCH] functionObjects::age: add optinoal diffusion term and
 convergence control

to enable the calculation of the residence time for a fluid; mainly used in HVAC
analysis. E.g. residence time of air inside a ventilated room, see the new
tutorial roomResidenceTime.

Contributed by Tobias Holzmann
---
 src/functionObjects/field/age/age.C           | 109 ++++++--
 src/functionObjects/field/age/age.H           |  24 +-
 .../simpleFoam/roomResidenceTime/0/U          |  43 ++++
 .../simpleFoam/roomResidenceTime/0/epsilon    |  45 ++++
 .../simpleFoam/roomResidenceTime/0/k          |  45 ++++
 .../simpleFoam/roomResidenceTime/0/nut        |  44 ++++
 .../simpleFoam/roomResidenceTime/0/p          |  42 +++
 .../simpleFoam/roomResidenceTime/Allclean     |  11 +
 .../simpleFoam/roomResidenceTime/Allrun       |  16 ++
 .../constant/transportProperties              |  23 ++
 .../constant/turbulenceProperties             |  30 +++
 .../simpleFoam/roomResidenceTime/system/age   |  28 ++
 .../roomResidenceTime/system/blockMeshDict    | 240 ++++++++++++++++++
 .../roomResidenceTime/system/controlDict      |  53 ++++
 .../roomResidenceTime/system/flowRatePatch    |  19 ++
 .../roomResidenceTime/system/fvSchemes        |  60 +++++
 .../roomResidenceTime/system/fvSolution       |  72 ++++++
 .../roomResidenceTime/system/probes1          |  50 ++++
 .../roomResidenceTime/system/probes2          |  50 ++++
 .../roomResidenceTime/validation/Allclean     |   2 +
 .../roomResidenceTime/validation/Allrun       |  37 +++
 .../validation/measurement_Pos1               |  12 +
 .../validation/measurement_Pos2               |  10 +
 .../validation/plotPos1Data.gplt              |  15 ++
 .../validation/plotPos2Data.gplt              |  15 ++
 25 files changed, 1064 insertions(+), 31 deletions(-)
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/0/U
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/0/epsilon
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/0/k
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/0/nut
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/0/p
 create mode 100755 tutorials/incompressible/simpleFoam/roomResidenceTime/Allclean
 create mode 100755 tutorials/incompressible/simpleFoam/roomResidenceTime/Allrun
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/constant/transportProperties
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/constant/turbulenceProperties
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/system/age
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/system/blockMeshDict
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/system/controlDict
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/system/flowRatePatch
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/system/fvSchemes
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/system/fvSolution
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/system/probes1
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/system/probes2
 create mode 100755 tutorials/incompressible/simpleFoam/roomResidenceTime/validation/Allclean
 create mode 100755 tutorials/incompressible/simpleFoam/roomResidenceTime/validation/Allrun
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/validation/measurement_Pos1
 create mode 100644 tutorials/incompressible/simpleFoam/roomResidenceTime/validation/measurement_Pos2
 create mode 100755 tutorials/incompressible/simpleFoam/roomResidenceTime/validation/plotPos1Data.gplt
 create mode 100755 tutorials/incompressible/simpleFoam/roomResidenceTime/validation/plotPos2Data.gplt

diff --git a/src/functionObjects/field/age/age.C b/src/functionObjects/field/age/age.C
index cb90801cbd..0222e7816f 100644
--- a/src/functionObjects/field/age/age.C
+++ b/src/functionObjects/field/age/age.C
@@ -24,8 +24,9 @@ License
 \*---------------------------------------------------------------------------*/
 
 #include "age.H"
-#include "fvmDdt.H"
 #include "fvmDiv.H"
+#include "fvmLaplacian.H"
+#include "turbulenceModel.H"
 #include "inletOutletFvPatchField.H"
 #include "wallFvPatch.H"
 #include "zeroGradientFvPatchField.H"
@@ -65,6 +66,26 @@ Foam::wordList Foam::functionObjects::age::patchTypes() const
 }
 
 
+bool Foam::functionObjects::age::converged
+(
+    const int nCorr,
+    const scalar initialResidual
+) const
+{
+    if (initialResidual < tolerance_)
+    {
+        Info<< "Field " << typeName
+            << " converged in " << nCorr << " correctors\n" << endl;
+
+        return true;
+    }
+    else
+    {
+        return false;
+    }
+}
+
+
 // * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
 Foam::functionObjects::age::age
@@ -74,12 +95,7 @@ Foam::functionObjects::age::age
     const dictionary& dict
 )
 :
-    fvMeshFunctionObject(name, runTime, dict),
-    phiName_(),
-    rhoName_(),
-    nCorr_(0),
-    schemesField_()
-
+    fvMeshFunctionObject(name, runTime, dict)
 {
     read(dict);
 }
@@ -97,10 +113,10 @@ bool Foam::functionObjects::age::read(const dictionary& dict)
 {
     phiName_ = dict.lookupOrDefault<word>("phi", "phi");
     rhoName_ = dict.lookupOrDefault<word>("rho", "rho");
-
-    dict.readIfPresent("nCorr", nCorr_);
-
+    nCorr_ = dict.lookupOrDefault<int>("nCorr", 5);
     schemesField_ = dict.lookupOrDefault<word>("schemesField", typeName);
+    diffusion_ = dict.lookupOrDefault<Switch>("diffusion", false);
+    tolerance_ = dict.lookupOrDefault<scalar>("tolerance", 1e-5);
 
     return true;
 }
@@ -114,7 +130,7 @@ bool Foam::functionObjects::age::execute()
 
 bool Foam::functionObjects::age::write()
 {
-    volScalarField t
+    volScalarField age
     (
         IOobject
         (
@@ -152,36 +168,83 @@ bool Foam::functionObjects::age::write()
         const volScalarField& rho =
             mesh_.lookupObject<volScalarField>(rhoName_);
 
-        for (label i = 0; i <= nCorr_; ++ i)
+        tmp<volScalarField> tmuEff;
+        word laplacianScheme;
+
+        if (diffusion_)
         {
-            fvScalarMatrix tEqn
+            tmuEff =
+                mesh_.lookupObject<turbulenceModel>
+                (
+                    turbulenceModel::propertiesName
+                ).muEff();
+
+            laplacianScheme =
+                "laplacian(" + tmuEff().name() + ',' + schemesField_ + ")";
+        }
+
+        for (int i=0; i<=nCorr_; i++)
+        {
+            fvScalarMatrix ageEqn
             (
-                fvm::div(phi, t, divScheme) == rho
+                fvm::div(phi, age, divScheme) == rho
             );
 
-            tEqn.relax(relaxCoeff);
+            if (diffusion_)
+            {
+                ageEqn -= fvm::laplacian(tmuEff(), age, laplacianScheme);
+            }
 
-            tEqn.solve(schemesField_);
+            ageEqn.relax(relaxCoeff);
+
+            if (converged(i, ageEqn.solve(schemesField_).initialResidual()))
+            {
+                break;
+            };
         }
     }
     else
     {
-        for (label i = 0; i <= nCorr_; ++ i)
+        tmp<volScalarField> tnuEff;
+        word laplacianScheme;
+
+        if (diffusion_)
         {
-            fvScalarMatrix tEqn
+            tnuEff =
+                mesh_.lookupObject<turbulenceModel>
+                (
+                    turbulenceModel::propertiesName
+                ).nuEff();
+
+            laplacianScheme =
+                "laplacian(" + tnuEff().name() + ',' + schemesField_ + ")";
+        }
+
+        for (int i=0; i<=nCorr_; i++)
+        {
+            fvScalarMatrix ageEqn
             (
-                fvm::div(phi, t, divScheme) == dimensionedScalar(1)
+                fvm::div(phi, age, divScheme) == dimensionedScalar(1)
             );
 
-            tEqn.relax(relaxCoeff);
+            if (diffusion_)
+            {
+                ageEqn -= fvm::laplacian(tnuEff(), age, laplacianScheme);
+            }
 
-            tEqn.solve(schemesField_);
+            ageEqn.relax(relaxCoeff);
+
+            if (converged(i, ageEqn.solve(schemesField_).initialResidual()))
+            {
+                break;
+            }
         }
     }
 
-    Info<< "Min/max age:" << min(t).value() << ' ' << max(t).value() << endl;
+    Info<< "Min/max age:" << min(age).value()
+        << ' ' << max(age).value() << endl;
 
-    t.write();
+    age.write();
 
     return true;
 }
diff --git a/src/functionObjects/field/age/age.H b/src/functionObjects/field/age/age.H
index 9b59641389..f8a5088efe 100644
--- a/src/functionObjects/field/age/age.H
+++ b/src/functionObjects/field/age/age.H
@@ -40,12 +40,14 @@ Description
 
 Usage
     \table
-        Property | Description                   | Required | Default value
-        phi      | The name of the flux field    | no       | phi
-        rho      | The name of the density field | no       | rho
-        nCorr    | The number of correctors      | no       | 0
+        Property  | Description                   | Required | Default value
+        phi       | The name of the flux field    | no       | phi
+        rho       | The name of the density field | no       | rho
+        nCorr     | The maximum number of correctors | no       | 5
         schemesField | The name of the field from which schemes are taken | \\
         no | age
+        diffusion | Switch to turn on/off the diffusion term | no | off
+        tolerance  | Solver residual control       | no       | 1e-5
     \endtable
 
     \verbatim
@@ -57,9 +59,6 @@ Usage
         writeControl    writeTime;
         writeInterval   1;
 
-        phi             phi;
-        rho             rho;
-        nCorr           10;
         schemesField    k;
     }
     \endverbatim
@@ -99,17 +98,26 @@ class age
         word rhoName_;
 
         //- Number of corrections
-        label nCorr_;
+        int nCorr_;
 
         //- Name of field from which schemes are taken
         word schemesField_;
 
+        //- Switch to turn on/off the diffusion term
+        Switch diffusion_;
+
+        //- Convergence tolerance
+        scalar tolerance_;
+
 
     // Private Member Functions
 
         //- The list of patch types for the age field
         wordList patchTypes() const;
 
+        //- Check convergence
+        bool converged(const int nCorr, const scalar initialResidual) const;
+
 
 public:
 
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/0/U b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/U
new file mode 100644
index 0000000000..58f7d1e4de
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/U
@@ -0,0 +1,43 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       volVectorField;
+    location    "0";
+    object      U;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+dimensions      [0 1 -1 0 0 0 0];
+
+internalField   uniform (0 0 0);
+
+boundaryField
+{
+    walls
+    {
+        type            noSlip;
+    }
+
+    inlet
+    {
+        type            fixedValue;
+        value           uniform (1.68 0 0);
+    }
+
+    outlet
+    {
+        type            pressureInletOutletVelocity;
+        value           uniform (0 0 0);
+    }
+}
+
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/0/epsilon b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/epsilon
new file mode 100644
index 0000000000..54ccea40e8
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/epsilon
@@ -0,0 +1,45 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       volScalarField;
+    location    "0";
+    object      epsilon;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+dimensions      [0 2 -3 0 0 0 0];
+
+internalField   uniform 0.23;
+
+boundaryField
+{
+    walls
+    {
+        type            epsilonWallFunction;
+        value           $internalField;
+    }
+
+    inlet
+    {
+        type            turbulentMixingLengthDissipationRateInlet;
+        mixingLength    0.0168;
+        value           $internalField;
+    }
+
+    outlet
+    {
+        type            inletOutlet;
+        inletValue      $internalField;
+    }
+}
+
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/0/k b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/k
new file mode 100644
index 0000000000..341479b846
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/k
@@ -0,0 +1,45 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       volScalarField;
+    location    "0";
+    object      k;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+dimensions      [0 2 -2 0 0 0 0];
+
+internalField   uniform 8e-2;
+
+boundaryField
+{
+    walls
+    {
+        type            kqRWallFunction;
+        value           $internalField;
+    }
+
+    inlet
+    {
+        type            turbulentIntensityKineticEnergyInlet;
+        intensity       0.14;
+        value           $internalField;
+    }
+
+    outlet
+    {
+        type            inletOutlet;
+        inletValue      $internalField;
+    }
+}
+
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/0/nut b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/nut
new file mode 100644
index 0000000000..36e6610825
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/nut
@@ -0,0 +1,44 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       volScalarField;
+    location    "0";
+    object      nut;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+dimensions      [0 2 -1 0 0 0 0];
+
+internalField   uniform 0;
+
+boundaryField
+{
+    walls
+    {
+        type            nutkWallFunction;
+        value           uniform 0;
+    }
+
+    inlet
+    {
+        type            calculated;
+        value           uniform 0;
+    }
+
+    outlet
+    {
+        type            calculated;
+        value           uniform 0;
+    }
+}
+
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/0/p b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/p
new file mode 100644
index 0000000000..535966aaec
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/0/p
@@ -0,0 +1,42 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       volScalarField;
+    location    "0";
+    object      p;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+dimensions      [0 2 -2 0 0 0 0];
+
+internalField   uniform 0;
+
+boundaryField
+{
+    walls
+    {
+        type            zeroGradient;
+    }
+
+    inlet
+    {
+        type            zeroGradient;
+    }
+
+    outlet
+    {
+        type            fixedValue;
+        value           uniform 0;
+    }
+}
+
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/Allclean b/tutorials/incompressible/simpleFoam/roomResidenceTime/Allclean
new file mode 100755
index 0000000000..5cf60b8b16
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/Allclean
@@ -0,0 +1,11 @@
+#!/bin/sh
+cd ${0%/*} || exit 1    # Run from this directory
+
+# Source tutorial clean functions
+. $WM_PROJECT_DIR/bin/tools/CleanFunctions
+
+cleanCase
+
+(cd validation && ./Allclean)
+
+#------------------------------------------------------------------------------
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/Allrun b/tutorials/incompressible/simpleFoam/roomResidenceTime/Allrun
new file mode 100755
index 0000000000..9344689094
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/Allrun
@@ -0,0 +1,16 @@
+#!/bin/sh
+cd ${0%/*} || exit 1    # Run from this directory
+
+# Source tutorial run functions
+. $WM_PROJECT_DIR/bin/tools/RunFunctions
+
+runApplication blockMesh
+runApplication simpleFoam
+runApplication -s age simpleFoam -latestTime -postProcess -func age
+runApplication -s probes1 postProcess -func probes1 -latestTime
+runApplication -s probes2 postProcess -func probes2 -latestTime
+runApplication -s flowRatePatch postProcess -func flowRatePatch -latestTime
+
+(cd validation && ./Allrun $*)
+
+#------------------------------------------------------------------------------
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/constant/transportProperties b/tutorials/incompressible/simpleFoam/roomResidenceTime/constant/transportProperties
new file mode 100644
index 0000000000..637921a6f7
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/constant/transportProperties
@@ -0,0 +1,23 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    location    "constant";
+    object      transportProperties;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+transportModel  Newtonian;
+
+// Air at 23 degC
+nu              [0 2 -1 0 0 0 0] 1.56225e-05;
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/constant/turbulenceProperties b/tutorials/incompressible/simpleFoam/roomResidenceTime/constant/turbulenceProperties
new file mode 100644
index 0000000000..a652d98461
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/constant/turbulenceProperties
@@ -0,0 +1,30 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    location    "constant";
+    object      turbulenceProperties;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+simulationType RAS;
+
+RAS
+{
+    RASModel        kEpsilon;
+
+    turbulence      on;
+
+    printCoeffs     on;
+}
+
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/system/age b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/age
new file mode 100644
index 0000000000..605ae78f7e
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/age
@@ -0,0 +1,28 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+Description
+    Solves a transport equation to determine the time taken for a particle to
+    convect from an inlet to the location in the flow.
+
+    This will output a field, age, with units of time. This field needs a
+    solver setting in fvSolution and a div(phi,age) scheme in fvSchemes.
+    Alternatively, a schemesField entry can be used to reuse settings from
+    another field.
+
+    The number of correctors, nCorr, determines how many times the solution is
+    repeated to iterate away any non-linearities in the choice of scheme. If
+    the divergence scheme is set to upwind, no corrections will be necessary.
+
+\*---------------------------------------------------------------------------*/
+
+type            age;
+libs            ("libfieldFunctionObjects.so");
+
+diffusion       true;
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/system/blockMeshDict b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/blockMeshDict
new file mode 100644
index 0000000000..54c1eb79f1
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/blockMeshDict
@@ -0,0 +1,240 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      blockMeshDict;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+convertToMeters 1;
+
+vertices
+(
+    (0 0 0)             // 0
+    (0 0 2.05)
+    (0 1.65 2.05)
+    (0 1.65 0)
+
+    (3.8 0 0)           // 4
+    (3.8 0 2.05)
+    (3.8 1.65 2.05)
+    (3.8 1.65 0)
+
+    (4 0 0)             // 8
+    (4 0 2.05)
+    (4 1.65 2.05)
+    (4 1.65 0)
+
+    (4.2 0 0)           // 12
+    (4.2 0 2.05)
+    (4.2 1.65 2.05)
+    (4.2 1.65 0)
+
+    (0 1.95 0)          // 16
+    (0 1.95 2.05)
+    (3.8 1.95 0)
+    (3.8 1.95 2.05)
+
+    (4 1.95 0)          // 20
+    (4 1.95 2.05)
+    (4.2 1.95 0)
+    (4.2 1.95 2.05)
+
+    (0 3.6 0)          // 24
+    (0 3.6 2.05)
+    (3.8 3.6 0)
+    (3.8 3.6 2.05)
+
+    (4 3.6 0)          // 28
+    (4 3.6 2.05)
+    (4.2 3.6 0)
+    (4.2 3.6 2.05)
+
+    (0 0 2.25)         // 32
+    (0 1.65 2.25)
+    (3.8 0 2.25)
+    (3.8 1.65 2.25)
+
+    (4 0 2.25)         // 36
+    (4 1.65 2.25)
+    (4.2 0 2.25)
+    (4.2 1.65 2.25)
+
+    (0 1.95 2.25)      // 40
+    (3.8 1.95 2.25)
+    (4 1.95 2.25)
+    (4.2 1.95 2.25)
+
+    (0 3.6 2.25)       // 44
+    (3.8 3.6 2.25)
+    (4 3.6 2.25)
+    (4.2 3.6 2.25)
+
+    (0 0 3)            // 48
+    (0 1.65 3)
+    (3.8 0 3)
+    (3.8 1.65 3)
+
+    (4 0 3)            // 52
+    (4 1.65 3)
+    (4.2 0 3)
+    (4.2 1.65 3)
+
+    (0 1.95 3)         // 56
+    (0 3.6 3)
+    (3.8 1.95 3)
+    (3.8 3.6 3)
+
+    (4 1.95 3)         // 60
+    (4 3.6 3)
+    (4.2 1.95 3)
+    (4.2 3.6 3)
+);
+
+blocks
+(
+    hex (0 3 2 1 4 7 6 5)
+    (21 20 35)
+    simpleGrading (1 1 1)
+
+    hex (4 7 6 5 8 11 10 9)
+    (21 20 2)
+    simpleGrading (1 1 1)
+
+    hex (8 11 10 9 12 15 14 13)
+    (21 20 2)
+    simpleGrading (1 1 1)
+
+    hex (3 16 17 2 7 18 19 6)
+    (4 20 35)
+    simpleGrading (1 1 1)
+
+    hex (7 18 19 6 11 20 21  10)
+    (4 20 2)
+    simpleGrading (1 1 1)
+
+    hex (11 20 21 10 15 22 23 14)
+    (4 20 2)
+    simpleGrading (1 1 1)
+
+    hex (16 24 25 17 18 26 27 19)
+    (21 20 35)
+    simpleGrading (1 1 1)
+
+    hex (18 26 27 19 20 28 29 21)
+    (21 20 2)
+    simpleGrading (1 1 1)
+
+    hex (20 28 29 21 22 30 31 23)
+    (21 20 2)
+    simpleGrading (1 1 1)
+
+    hex (1 2 33 32 5 6 35 34)
+    (21 2 35)
+    simpleGrading (1 1 1)
+
+    hex (5 6 35 34 9 10 37 36)
+    (21 2 2)
+    simpleGrading (1 1 1)
+
+    hex (9 10 37 36 13 14 39 38)
+    (21 2 2)
+    simpleGrading (1 1 1)
+
+    hex (2 17 40 33 6 19 41 35)
+    (4 2 35)
+    simpleGrading (1 1 1)
+
+    hex (6 19 41 35 10 21 42 37)
+    (4 2 2)
+    simpleGrading (1 1 1)
+
+    hex (10 21 42 37 14 23 43 39)
+    (4 2 2)
+    simpleGrading (1 1 1)
+
+    hex (17 25 44 40 19 27 45 41)
+    (21 2 35)
+    simpleGrading (1 1 1)
+
+    hex (19 27 45 41 21 29 46 42)
+    (21 2 2)
+    simpleGrading (1 1 1)
+
+    hex (21 29 46 42 23 31 47 43)
+    (21 2 2)
+    simpleGrading (1 1 1)
+
+    hex (32 33 49 48 34 35 51 50)
+    (21 8 35)
+    simpleGrading (1 1 1)
+
+    hex (34 35 51 50 36 37 53 52)
+    (21 8 2)
+    simpleGrading (1 1 1)
+
+    hex (36 37 53 52 38 39 55 54)
+    (21 8 2)
+    simpleGrading (1 1 1)
+
+    hex (33 40 56 49 35 41 58 51)
+    (4 8 35)
+    simpleGrading (1 1 1)
+
+    hex (35 41 58 51 37 42 60 53)
+    (4 8 2)
+    simpleGrading (1 1 1)
+
+    hex (37 42 60 53 39 43 62 55)
+    (4 8 2)
+    simpleGrading (1 1 1)
+
+    hex (40 44 57 56 41 45 59 58)
+    (21 8 35)
+    simpleGrading (1 1 1)
+
+    hex (41 45 59 58 42 46 61 60)
+    (21 8 2)
+    simpleGrading (1 1 1)
+
+    hex (42 46 61 60 43 47 63 62)
+    (21 8 2)
+    simpleGrading (1 1 1)
+);
+
+defaultPatch
+{
+    name walls;
+    type wall;
+}
+
+boundary
+(
+    inlet
+    {
+        type patch;
+        faces
+        (
+            (2 17 40 33)
+        );
+    }
+
+    outlet
+    {
+        type patch;
+        faces
+        (
+            (51 58 60 53)
+        );
+    }
+);
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/system/controlDict b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/controlDict
new file mode 100644
index 0000000000..3444f311cf
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/controlDict
@@ -0,0 +1,53 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    location    "system";
+    object      controlDict;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+application     simpleFoam;
+
+startFrom       startTime;
+
+startTime       0;
+
+stopAt          endTime;
+
+endTime         2000;
+
+deltaT          1;
+
+writeControl    timeStep;
+
+writeInterval   250;
+
+purgeWrite      0;
+
+writeFormat     ascii;
+
+writePrecision  6;
+
+writeCompression off;
+
+timeFormat      general;
+
+timePrecision   6;
+
+runTimeModifiable true;
+
+functions
+{
+    #includeFunc residuals
+}
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/system/flowRatePatch b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/flowRatePatch
new file mode 100644
index 0000000000..d1e8dae85c
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/flowRatePatch
@@ -0,0 +1,19 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+Description
+    Calculates the flow rate through a specified patch by summing the flux on
+    patch faces.  For solvers where the flux is volumetric, the flow rate is
+    volumetric; where flux is mass flux, the flow rate is mass flow rate.
+
+\*---------------------------------------------------------------------------*/
+
+name    inlet;
+
+#includeEtc "caseDicts/postProcessing/flowRate/flowRatePatch.cfg"
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/system/fvSchemes b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/fvSchemes
new file mode 100644
index 0000000000..7ccfdb31be
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/fvSchemes
@@ -0,0 +1,60 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    location    "system";
+    object      fvSchemes;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+ddtSchemes
+{
+    default         steadyState;
+}
+
+gradSchemes
+{
+    default         Gauss linear;
+}
+
+divSchemes
+{
+    default         none;
+    div(phi,U)      bounded Gauss upwind;
+    div(phi,k)      bounded Gauss upwind;
+    div(phi,epsilon) bounded Gauss upwind;
+    div((nuEff*dev2(T(grad(U))))) Gauss linear;
+
+    div(phi,age)    bounded Gauss upwind;
+}
+
+laplacianSchemes
+{
+    default         Gauss linear orthogonal;
+}
+
+interpolationSchemes
+{
+    default         linear;
+}
+
+snGradSchemes
+{
+    default         orthogonal;
+}
+
+wallDist
+{
+    method meshWave;
+}
+
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/system/fvSolution b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/fvSolution
new file mode 100644
index 0000000000..76aa352c48
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/fvSolution
@@ -0,0 +1,72 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    location    "system";
+    object      fvSolution;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+solvers
+{
+    p
+    {
+        solver          GAMG;
+        tolerance       1e-08;
+        relTol          0.1;
+        smoother        GaussSeidel;
+    }
+
+    "(U|k|epsilon)"
+    {
+        solver          PBiCG;
+        preconditioner  DILU;
+        tolerance       1e-08;
+        relTol          0.1;
+    }
+
+    age
+    {
+        $U;
+        relTol          0.001;
+    }
+}
+
+SIMPLE
+{
+    consistent          yes;
+
+    residualControl
+    {
+        p               1e-3;
+        U               1e-4;
+        "(k|epsilon)"   1e-4;
+    }
+}
+
+relaxationFactors
+{
+    fields
+    {
+        p               1;
+    }
+
+    equations
+    {
+        U               0.95;
+        k               0.7;
+        epsilon         0.7;
+        age             1;
+    }
+}
+
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/system/probes1 b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/probes1
new file mode 100644
index 0000000000..0604c87225
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/probes1
@@ -0,0 +1,50 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+Description
+    Writes out values of fields from cells nearest to specified locations.
+
+\*---------------------------------------------------------------------------*/
+
+#includeEtc "caseDicts/postProcessing/probes/probes.cfg"
+
+fields (age);
+probeLocations
+(
+    (1.13 1.8 0.0)
+    (1.13 1.8 0.1)
+    (1.13 1.8 0.2)
+    (1.13 1.8 0.3)
+    (1.13 1.8 0.4)
+    (1.13 1.8 0.5)
+    (1.13 1.8 0.6)
+    (1.13 1.8 0.7)
+    (1.13 1.8 0.8)
+    (1.13 1.8 0.9)
+    (1.13 1.8 1.0)
+    (1.13 1.8 1.1)
+    (1.13 1.8 1.2)
+    (1.13 1.8 1.3)
+    (1.13 1.8 1.4)
+    (1.13 1.8 1.5)
+    (1.13 1.8 1.6)
+    (1.13 1.8 1.7)
+    (1.13 1.8 1.8)
+    (1.13 1.8 1.9)
+    (1.13 1.8 2.1)
+    (1.13 1.8 2.2)
+    (1.13 1.8 2.3)
+    (1.13 1.8 2.4)
+    (1.13 1.8 2.5)
+    (1.13 1.8 2.6)
+    (1.13 1.8 2.7)
+    (1.13 1.8 2.8)
+    (1.13 1.8 2.9)
+    (1.13 1.8 3.0)
+);
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/system/probes2 b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/probes2
new file mode 100644
index 0000000000..c66ef5deaf
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/system/probes2
@@ -0,0 +1,50 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+Description
+    Writes out values of fields from cells nearest to specified locations.
+
+\*---------------------------------------------------------------------------*/
+
+#includeEtc "caseDicts/postProcessing/probes/probes.cfg"
+
+fields (age);
+probeLocations
+(
+    (3.2 1.8 0.0)
+    (3.2 1.8 0.1)
+    (3.2 1.8 0.2)
+    (3.2 1.8 0.3)
+    (3.2 1.8 0.4)
+    (3.2 1.8 0.5)
+    (3.2 1.8 0.6)
+    (3.2 1.8 0.7)
+    (3.2 1.8 0.8)
+    (3.2 1.8 0.9)
+    (3.2 1.8 1.0)
+    (3.2 1.8 1.1)
+    (3.2 1.8 1.2)
+    (3.2 1.8 1.3)
+    (3.2 1.8 1.4)
+    (3.2 1.8 1.5)
+    (3.2 1.8 1.6)
+    (3.2 1.8 1.7)
+    (3.2 1.8 1.8)
+    (3.2 1.8 1.9)
+    (3.2 1.8 2.1)
+    (3.2 1.8 2.2)
+    (3.2 1.8 2.3)
+    (3.2 1.8 2.4)
+    (3.2 1.8 2.5)
+    (3.2 1.8 2.6)
+    (3.2 1.8 2.7)
+    (3.2 1.8 2.8)
+    (3.2 1.8 2.9)
+    (3.2 1.8 3.0)
+);
+
+// ************************************************************************* //
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/Allclean b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/Allclean
new file mode 100755
index 0000000000..23c5821e9c
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/Allclean
@@ -0,0 +1,2 @@
+#!/bin/bash
+rm -f positionsZ age* *.eps *_OF
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/Allrun b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/Allrun
new file mode 100755
index 0000000000..53d63276bf
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/Allrun
@@ -0,0 +1,37 @@
+#!/bin/bash
+./Allclean
+
+# ------ Pos 1 Evaluation
+tail -n 1 ../postProcessing/probes1/*/age | xargs | sed 's/ /\n/g' | tail -n 30 > ageValues
+head -n 30 ../postProcessing/probes1/*/age | cut -d' ' -f6 | cut -d')' -f1 > positionsZ
+
+# Build dimless age value
+V=45.36
+Vdot=`cat ../postProcessing/flowRatePatch/0/surfaceFieldValue.dat | tail -n 1 | xargs | cut -d' ' -f2`
+Vdot=`echo $Vdot | sed 's/e/*10^/'`
+
+while IFS= read -r line
+do
+    echo "scale=5; $line/($V/($Vdot*-1.))" | bc >> ageDimless1
+done < "ageValues"
+
+paste positionsZ ageDimless1 > Pos1_OF
+
+
+# ------ Pos 2 Evaluation
+tail -n 1 ../postProcessing/probes2/*/age | xargs | sed 's/ /\n/g' | tail -n 30 > ageValues
+head -n 30 ../postProcessing/probes2/*/age | cut -d' ' -f6 | cut -d')' -f1 > positionsZ
+
+# Build dimless age value
+
+while IFS= read -r line
+do
+    echo "scale=5; $line/($V/($Vdot*-1.))" | bc >> ageDimless2
+done < "ageValues"
+
+paste positionsZ ageDimless2 > Pos2_OF
+
+# ------ Plot the results
+gnuplot plot*
+
+#------------------------------------------------------------------------------
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/measurement_Pos1 b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/measurement_Pos1
new file mode 100644
index 0000000000..30bab60c3d
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/measurement_Pos1
@@ -0,0 +1,12 @@
+# Bartak M. et al.: Experimental and numerical study of local mean age of air
+# x = 1.13m | y = 1.8 m
+# Data extracted from plots as the original data were not given
+#
+# Age [dimless]      z coordinate       Age [s] = Dimless * 45.36 / 0.1
+# ---------------------------------------------------------------------
+0.9999999999999998 0.18907723824317335 453.6
+1.0135746606334840 0.99995497624997220 459.7
+0.9773755656108594 1.09963755881227330 443.3
+0.6425339366515836 2.00180095000112600 291.5
+0.3981900452488687 2.09754395443596500 180.6
+0.9773755656108594 2.82600571801625400 443.3
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/measurement_Pos2 b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/measurement_Pos2
new file mode 100644
index 0000000000..4fed34dbce
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/measurement_Pos2
@@ -0,0 +1,10 @@
+# Bartak M. et al.: Experimental and numerical study of local mean age of air
+# x = 3.20m | y = 1.8 m
+# Data extracted from plots as the original data were not given
+#
+# Age [dimless]      z coordinate
+# ---------------------------------------
+0.9842696629213484 0.1782682512733449
+1.0966292134831463 1.1052631578947367
+0.7550561797752810 2.0984719864176570
+1.0022471910112358 2.8268251273344650
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/plotPos1Data.gplt b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/plotPos1Data.gplt
new file mode 100755
index 0000000000..536beefcd1
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/plotPos1Data.gplt
@@ -0,0 +1,15 @@
+#!/bin/gnuplot
+#------------------------------------------------------------------------------
+set grid
+set title "Comparison at x =1.13 m, y = 1.8 m"
+set xlabel "Dimensionless Age Quantity [-]"
+set ylabel "z-coordinate [m]"
+set xrange [0:2]
+set yrange [0:3]
+#------------------------------------------------------------------------------
+set terminal postscript eps color enhanced "Helveicta,20"
+set output 'Pos1_Comparison.eps'
+plot \
+'measurement_Pos1' using 1:2 w p pt 7 t 'Measurement', \
+'Pos1_OF' using 2:1 w l t 'OpenFOAM'
+#------------------------------------------------------------------------------
diff --git a/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/plotPos2Data.gplt b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/plotPos2Data.gplt
new file mode 100755
index 0000000000..18e0e553b0
--- /dev/null
+++ b/tutorials/incompressible/simpleFoam/roomResidenceTime/validation/plotPos2Data.gplt
@@ -0,0 +1,15 @@
+#!/bin/gnuplot
+#------------------------------------------------------------------------------
+set grid
+set title "Comparison at x = 3.2 m, y = 1.8 m"
+set xlabel "Dimensionless Age Quantity [-]"
+set ylabel "z-coordinate [m]"
+set xrange [0:2]
+set yrange [0:3]
+#------------------------------------------------------------------------------
+set terminal postscript eps color enhanced "Helveicta,20"
+set output 'Pos2_Comparison.eps'
+plot \
+'measurement_Pos2' using 1:2 w p pt 7 t 'Measurement', \
+'Pos2_OF' using 2:1 w l t 'OpenFOAM'
+#------------------------------------------------------------------------------