ENH: add time ramping to surfaceNormalFixedValue (#1407)

- alternatively can use uniformNormalFixedValue with PatchFunction1
  specification and temporal ramping.

TUT: add ramped example for simpleCar

src/finiteVolume/Make/files

@@ -209,6 +209,7 @@ $(derivedFvPatchFields)/uniformFixedValue/uniformFixedValueFvPatchFields.C
 $(derivedFvPatchFields)/uniformInletOutlet/uniformInletOutletFvPatchFields.C
 $(derivedFvPatchFields)/uniformJump/uniformJumpFvPatchFields.C
 $(derivedFvPatchFields)/uniformJumpAMI/uniformJumpAMIFvPatchFields.C
+$(derivedFvPatchFields)/uniformNormalFixedValue/uniformNormalFixedValueFvPatchVectorField.C
 $(derivedFvPatchFields)/uniformTotalPressure/uniformTotalPressureFvPatchScalarField.C
 $(derivedFvPatchFields)/variableHeightFlowRate/variableHeightFlowRateFvPatchField.C
 $(derivedFvPatchFields)/variableHeightFlowRateInletVelocity/variableHeightFlowRateInletVelocityFvPatchVectorField.C

src/finiteVolume/fields/fvPatchFields/derived/surfaceNormalFixedValue/surfaceNormalFixedValueFvPatchVectorField.C

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           |
+    \\  /    A nd           | Copyright (C) 2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011-2016 OpenFOAM Foundation
@@ -40,7 +40,8 @@ surfaceNormalFixedValueFvPatchVectorField
 )
 :
     fixedValueFvPatchVectorField(p, iF),
-    refValue_(p.size())
+    refValue_(p.size()),
+    ramp_(nullptr)
 {}
 
 
@@ -53,9 +54,22 @@ surfaceNormalFixedValueFvPatchVectorField
 )
 :
     fixedValueFvPatchVectorField(p, iF, dict, false),
-    refValue_("refValue", dict, p.size())
+    refValue_("refValue", dict, p.size()),
+    ramp_(nullptr)
 {
-    fvPatchVectorField::operator=(refValue_*patch().nf());
+    if (dict.found("ramp"))
+    {
+        ramp_ = Function1<scalar>::New("ramp", dict);
+    }
+
+    tmp<vectorField> tvalues(refValue_*patch().nf());
+
+    if (ramp_)
+    {
+        tvalues.ref() *= ramp_->value(this->db().time().timeOutputValue());
+    }
+
+    fvPatchVectorField::operator=(tvalues);
 }
 
 
@@ -69,36 +83,47 @@ surfaceNormalFixedValueFvPatchVectorField
 )
 :
     fixedValueFvPatchVectorField(p, iF),
-    refValue_(ptf.refValue_, mapper, pTraits<scalar>::zero)
+    refValue_(ptf.refValue_, mapper, pTraits<scalar>::zero),
+    ramp_(ptf.ramp_.clone())
 {
     // Note: refValue_ will have default value of 0 for unmapped faces. This
     // can temporarily happen during e.g. redistributePar. We should not
     // access ptf.patch() instead since redistributePar has destroyed this
     // at the time of mapping.
-    fvPatchVectorField::operator=(refValue_*patch().nf());
+
+    tmp<vectorField> tvalues(refValue_*patch().nf());
+
+    if (ramp_)
+    {
+        tvalues.ref() *= ramp_->value(this->db().time().timeOutputValue());
+    }
+
+    fvPatchVectorField::operator=(tvalues);
 }
 
 
 Foam::surfaceNormalFixedValueFvPatchVectorField::
 surfaceNormalFixedValueFvPatchVectorField
 (
-    const surfaceNormalFixedValueFvPatchVectorField& pivpvf
+    const surfaceNormalFixedValueFvPatchVectorField& ptf
 )
 :
-    fixedValueFvPatchVectorField(pivpvf),
+    fixedValueFvPatchVectorField(ptf),
-    refValue_(pivpvf.refValue_)
+    refValue_(ptf.refValue_),
+    ramp_(ptf.ramp_.clone())
 {}
 
 
 Foam::surfaceNormalFixedValueFvPatchVectorField::
 surfaceNormalFixedValueFvPatchVectorField
 (
-    const surfaceNormalFixedValueFvPatchVectorField& pivpvf,
+    const surfaceNormalFixedValueFvPatchVectorField& ptf,
     const DimensionedField<vector, volMesh>& iF
 )
 :
-    fixedValueFvPatchVectorField(pivpvf, iF),
+    fixedValueFvPatchVectorField(ptf, iF),
-    refValue_(pivpvf.refValue_)
+    refValue_(ptf.refValue_),
+    ramp_(ptf.ramp_.clone())
 {}
 
 
@@ -106,11 +131,11 @@ surfaceNormalFixedValueFvPatchVectorField
 
 void Foam::surfaceNormalFixedValueFvPatchVectorField::autoMap
 (
-    const fvPatchFieldMapper& m
+    const fvPatchFieldMapper& mapper
 )
 {
-    fixedValueFvPatchVectorField::autoMap(m);
+    fixedValueFvPatchVectorField::autoMap(mapper);
-    refValue_.autoMap(m);
+    refValue_.autoMap(mapper);
 }
 
 
@@ -136,7 +161,14 @@ void Foam::surfaceNormalFixedValueFvPatchVectorField::updateCoeffs()
         return;
     }
 
-    fvPatchVectorField::operator=(refValue_*patch().nf());
+    tmp<vectorField> tvalues(refValue_*patch().nf());
+
+    if (ramp_)
+    {
+        tvalues.ref() *= ramp_->value(this->db().time().timeOutputValue());
+    }
+
+    fvPatchVectorField::operator=(tvalues);
     fvPatchVectorField::updateCoeffs();
 }
 
@@ -145,6 +177,10 @@ void Foam::surfaceNormalFixedValueFvPatchVectorField::write(Ostream& os) const
 {
     fvPatchVectorField::write(os);
     refValue_.writeEntry("refValue", os);
+    if (ramp_)
+    {
+        ramp_->writeData(os);
+    }
 }
 
 

src/finiteVolume/fields/fvPatchFields/derived/surfaceNormalFixedValue/surfaceNormalFixedValueFvPatchVectorField.H

@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           |
+    \\  /    A nd           | Copyright (C) 2019 OpenCFD Ltd.
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
                             | Copyright (C) 2011-2016 OpenFOAM Foundation
@@ -35,8 +35,9 @@ Description
 
 Usage
     \table
-        Property     | Description             | Required    | Default value
+        Property     | Description                          | Required | Default
         refValue     | reference value                      | yes |
+        ramp         | time-based ramping                   | no  |
     \endtable
 
     Example of the boundary condition specification:
@@ -65,6 +66,7 @@ SourceFiles
 
 #include "fvPatchFields.H"
 #include "fixedValueFvPatchFields.H"
+#include "Function1.H"
 
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
@@ -79,10 +81,13 @@ class surfaceNormalFixedValueFvPatchVectorField
 :
     public fixedValueFvPatchVectorField
 {
-    // Private data
+    // Private Data
 
         scalarField refValue_;
 
+        //- Optional time ramping
+        autoPtr<Function1<scalar>> ramp_;
+
 
 public:
 

src/finiteVolume/fields/fvPatchFields/derived/uniformNormalFixedValue/uniformNormalFixedValueFvPatchVectorField.C

@@ -0,0 +1,205 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2019 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+\*---------------------------------------------------------------------------*/
+
+#include "uniformNormalFixedValueFvPatchVectorField.H"
+#include "addToRunTimeSelectionTable.H"
+#include "volFields.H"
+#include "fvPatchFieldMapper.H"
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::uniformNormalFixedValueFvPatchVectorField::
+uniformNormalFixedValueFvPatchVectorField
+(
+    const fvPatch& p,
+    const DimensionedField<vector, volMesh>& iF
+)
+:
+    fixedValueFvPatchVectorField(p, iF),
+    uniformValue_(nullptr),
+    ramp_(nullptr)
+{}
+
+
+Foam::uniformNormalFixedValueFvPatchVectorField::
+uniformNormalFixedValueFvPatchVectorField
+(
+    const fvPatch& p,
+    const DimensionedField<vector, volMesh>& iF,
+    const dictionary& dict
+)
+:
+    fixedValueFvPatchVectorField(p, iF, dict, false),
+    uniformValue_(PatchFunction1<scalar>::New(p.patch(), "uniformValue", dict)),
+    ramp_(nullptr)
+{
+    if (dict.found("ramp"))
+    {
+        ramp_ = Function1<scalar>::New("ramp", dict);
+    }
+
+    if (dict.found("value"))
+    {
+        fvPatchVectorField::operator=
+        (
+            vectorField("value", dict, p.size())
+        );
+    }
+    else
+    {
+        this->evaluate();
+    }
+}
+
+
+Foam::uniformNormalFixedValueFvPatchVectorField::
+uniformNormalFixedValueFvPatchVectorField
+(
+    const uniformNormalFixedValueFvPatchVectorField& ptf,
+    const fvPatch& p,
+    const DimensionedField<vector, volMesh>& iF,
+    const fvPatchFieldMapper& mapper
+)
+:
+    fixedValueFvPatchVectorField(p, iF),   // Don't map
+    uniformValue_(ptf.uniformValue_.clone(p.patch())),
+    ramp_(ptf.ramp_.clone())
+{
+    if (mapper.direct() && !mapper.hasUnmapped())
+    {
+        // Use mapping instead of re-evaluation
+        this->map(ptf, mapper);
+    }
+    else
+    {
+        // Evaluate since value not mapped
+        this->evaluate();
+    }
+}
+
+
+Foam::uniformNormalFixedValueFvPatchVectorField::
+uniformNormalFixedValueFvPatchVectorField
+(
+    const uniformNormalFixedValueFvPatchVectorField& ptf
+)
+:
+    fixedValueFvPatchVectorField(ptf),
+    uniformValue_(ptf.uniformValue_.clone(this->patch().patch())),
+    ramp_(ptf.ramp_.clone())
+{}
+
+
+Foam::uniformNormalFixedValueFvPatchVectorField::
+uniformNormalFixedValueFvPatchVectorField
+(
+    const uniformNormalFixedValueFvPatchVectorField& ptf,
+    const DimensionedField<vector, volMesh>& iF
+)
+:
+    fixedValueFvPatchVectorField(ptf, iF),
+    uniformValue_(ptf.uniformValue_.clone(this->patch().patch())),
+    ramp_(ptf.ramp_.clone())
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+void Foam::uniformNormalFixedValueFvPatchVectorField::autoMap
+(
+    const fvPatchFieldMapper& mapper
+)
+{
+    fixedValueFvPatchVectorField::autoMap(mapper);
+    uniformValue_().autoMap(mapper);
+
+    if (uniformValue_().constant())
+    {
+        // If mapper is not dependent on time we're ok to evaluate
+        this->evaluate();
+    }
+}
+
+
+void Foam::uniformNormalFixedValueFvPatchVectorField::rmap
+(
+    const fvPatchVectorField& ptf,
+    const labelList& addr
+)
+{
+    fixedValueFvPatchVectorField::rmap(ptf, addr);
+
+    const uniformNormalFixedValueFvPatchVectorField& tiptf =
+        refCast<const uniformNormalFixedValueFvPatchVectorField>(ptf);
+
+    uniformValue_().rmap(tiptf.uniformValue_(), addr);
+}
+
+
+void Foam::uniformNormalFixedValueFvPatchVectorField::updateCoeffs()
+{
+    if (updated())
+    {
+        return;
+    }
+
+    const scalar t = this->db().time().timeOutputValue();
+
+    tmp<vectorField> tvalues(uniformValue_->value(t)*patch().nf());
+
+    if (ramp_)
+    {
+        tvalues.ref() *= ramp_->value(t);
+    }
+
+    fvPatchVectorField::operator=(tvalues);
+    fvPatchVectorField::updateCoeffs();
+}
+
+
+void Foam::uniformNormalFixedValueFvPatchVectorField::write(Ostream& os) const
+{
+    fvPatchVectorField::write(os);
+    uniformValue_->writeData(os);
+    if (ramp_)
+    {
+        ramp_->writeData(os);
+    }
+    this->writeEntry("value", os);
+}
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+    makePatchTypeField
+    (
+        fvPatchVectorField,
+        uniformNormalFixedValueFvPatchVectorField
+    );
+}
+
+// ************************************************************************* //

src/finiteVolume/fields/fvPatchFields/derived/uniformNormalFixedValue/uniformNormalFixedValueFvPatchVectorField.H

@@ -0,0 +1,203 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2019 OpenCFD Ltd.
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+License
+    This file is part of OpenFOAM.
+
+    OpenFOAM is free software: you can redistribute it and/or modify it
+    under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
+    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+    for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
+
+Class
+    Foam::uniformNormalFixedValueFvPatchVectorField
+
+Group
+    grpGenericBoundaryConditions grpInletBoundaryConditions
+
+Description
+    This boundary condition provides a uniform surface-normal
+    vector boundary condition by its magnitude.
+
+Usage
+    \table
+        Property     | Description                          | Required | Default
+        uniformValue | uniform value                        | yes |
+        ramp         | time-based ramping                   | no  |
+    \endtable
+
+    Example of the boundary condition specification:
+    \verbatim
+    <patchName>
+    {
+        type            uniformNormalFixedValue;
+        uniformValue    constant -10;          // 10 INTO the domain
+    }
+    \endverbatim
+
+Note
+    Sign conventions:
+    - the value is positive for outward-pointing vectors
+
+See also
+    Foam::Function1Types
+    Foam::fixedValueFvPatchField
+    Foam::surfaceNormalFixedValueFvPatchVectorField
+    Foam::uniformFixedValueFvPatchVectorField
+
+SourceFiles
+    uniformNormalFixedValueFvPatchVectorField.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef uniformNormalFixedValueFvPatchVectorField_H
+#define uniformNormalFixedValueFvPatchVectorField_H
+
+#include "fvPatchFields.H"
+#include "fixedValueFvPatchFields.H"
+#include "PatchFunction1.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+
+/*---------------------------------------------------------------------------*\
+          Class uniformNormalFixedValueFvPatchVectorField Declaration
+\*---------------------------------------------------------------------------*/
+
+class uniformNormalFixedValueFvPatchVectorField
+:
+    public fixedValueFvPatchVectorField
+{
+    // Private Data
+
+        autoPtr<PatchFunction1<scalar>> uniformValue_;
+
+        //- Optional time ramping
+        autoPtr<Function1<scalar>> ramp_;
+
+
+public:
+
+    //- Runtime type information
+    TypeName("uniformNormalFixedValue");
+
+
+    // Constructors
+
+        //- Construct from patch and internal field
+        uniformNormalFixedValueFvPatchVectorField
+        (
+            const fvPatch&,
+            const DimensionedField<vector, volMesh>&
+        );
+
+        //- Construct from patch, internal field and dictionary
+        uniformNormalFixedValueFvPatchVectorField
+        (
+            const fvPatch&,
+            const DimensionedField<vector, volMesh>&,
+            const dictionary&
+        );
+
+        //- Construct by mapping given
+        //  uniformNormalFixedValueFvPatchVectorField
+        //  onto a new patch
+        uniformNormalFixedValueFvPatchVectorField
+        (
+            const uniformNormalFixedValueFvPatchVectorField&,
+            const fvPatch&,
+            const DimensionedField<vector, volMesh>&,
+            const fvPatchFieldMapper&
+        );
+
+        //- Construct as copy
+        uniformNormalFixedValueFvPatchVectorField
+        (
+            const uniformNormalFixedValueFvPatchVectorField&
+        );
+
+        //- Construct and return a clone
+        virtual tmp<fvPatchVectorField> clone() const
+        {
+            return tmp<fvPatchVectorField>
+            (
+                new uniformNormalFixedValueFvPatchVectorField(*this)
+            );
+        }
+
+        //- Construct as copy setting internal field reference
+        uniformNormalFixedValueFvPatchVectorField
+        (
+            const uniformNormalFixedValueFvPatchVectorField&,
+            const DimensionedField<vector, volMesh>&
+        );
+
+        //- Construct and return a clone setting internal field reference
+        virtual tmp<fvPatchVectorField> clone
+        (
+            const DimensionedField<vector, volMesh>& iF
+        ) const
+        {
+            return tmp<fvPatchVectorField>
+            (
+                new uniformNormalFixedValueFvPatchVectorField
+                (
+                    *this,
+                    iF
+                )
+            );
+        }
+
+
+    // Member Functions
+
+        // Mapping Functions
+
+            //- Map (and resize as needed) from self given a mapping object
+            virtual void autoMap
+            (
+                const fvPatchFieldMapper&
+            );
+
+            //- Reverse map the given fvPatchField onto this fvPatchField
+            virtual void rmap
+            (
+                const fvPatchVectorField&,
+                const labelList&
+            );
+
+
+        // Evaluation Functions
+
+            //- Update the coefficients associated with the patch field
+            virtual void updateCoeffs();
+
+
+        //- Write
+        virtual void write(Ostream& os) const;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

tutorials/incompressible/simpleFoam/simpleCar/0/U

@@ -18,12 +18,42 @@ dimensions      [0 1 -1 0 0 0 0];
 
 internalField   uniform (10 0 0);
 
+// Surface normal with time ramping
+intakeType1
+{
+    type            surfaceNormalFixedValue;
+    refValue        uniform 1.2;
+    ramp            table ((0 0) (10 1));
+}
+
+// Uniform surface normal with Function1 for ramping
+intakeType2
+{
+    type            uniformNormalFixedValue;
+    uniformValue    table ((0 0) (10 1.2));
+}
+
+// Uniform surface normal with time ramping
+intakeType3
+{
+    // Or directly with uniform value (ramping also possible)
+    type            uniformNormalFixedValue;
+    uniformValue    constant 1.2;
+    ramp            table ((0 0) (10 1));
+}
+
+
 boundaryField
 {
     inlet
     {
         type            fixedValue;
-        value           uniform (10 0 0);
+        value           $internalField;
+    }
+
+    airIntake
+    {
+        $intakeType1;
     }
 
     outlet
@@ -44,4 +74,8 @@ boundaryField
     }
 }
 
+
+#remove "intakeType.*"
+
+
 // ************************************************************************* //

tutorials/incompressible/simpleFoam/simpleCar/0/epsilon

@@ -24,40 +24,27 @@ boundaryField
     inlet
     {
         type            fixedValue;
-        value           uniform 0.125;
+        value           $internalField;
     }
-    outlet
+
-    {
+    "(body|upperWall|lowerWall)"
-        type            zeroGradient;
-    }
-    upperWall
     {
         type            epsilonWallFunction;
-        value           uniform 0.125;
+        value           $internalField;
-        Cmu             0.09;
-        kappa           0.41;
-        E               9.8;
-    }
-    lowerWall
-    {
-        type            epsilonWallFunction;
-        value           uniform 0.125;
-        Cmu             0.09;
-        kappa           0.41;
-        E               9.8;
-    }
-    body
-    {
-        type            epsilonWallFunction;
-        value           uniform 0.125;
         Cmu             0.09;
         kappa           0.41;
         E               9.8;
     }
+
     frontAndBack
     {
         type            empty;
     }
+
+    ".*"
+    {
+        type            zeroGradient;
+    }
 }
 
 

tutorials/incompressible/simpleFoam/simpleCar/0/k

@@ -24,31 +24,21 @@ boundaryField
     inlet
     {
         type            fixedValue;
-        value           uniform 0.375;
+        value           $internalField;
     }
-    outlet
+    "(body|upperWall|lowerWall)"
-    {
-        type            zeroGradient;
-    }
-    upperWall
     {
         type            kqRWallFunction;
-        value           uniform 0.375;
+        value           $internalField;
-    }
-    lowerWall
-    {
-        type            kqRWallFunction;
-        value           uniform 0.375;
-    }
-    body
-    {
-        type            kqRWallFunction;
-        value           uniform 0.375;
     }
     frontAndBack
     {
         type            empty;
     }
+    ".*"
+    {
+        type            zeroGradient;
+    }
 }
 
 

tutorials/incompressible/simpleFoam/simpleCar/0/nut

@@ -21,44 +21,25 @@ internalField   uniform 0;
 
 boundaryField
 {
-    inlet
+    "(body|upperWall|lowerWall)"
-    {
-        type            calculated;
-        value           uniform 0;
-    }
-    outlet
-    {
-        type            calculated;
-        value           uniform 0;
-    }
-    upperWall
     {
         type            nutkWallFunction;
         Cmu             0.09;
         kappa           0.41;
         E               9.8;
-        value           uniform 0;
+        value           $internalField;
-    }
-    lowerWall
-    {
-        type            nutkWallFunction;
-        Cmu             0.09;
-        kappa           0.41;
-        E               9.8;
-        value           uniform 0;
-    }
-    body
-    {
-        type            nutkWallFunction;
-        Cmu             0.09;
-        kappa           0.41;
-        E               9.8;
-        value           uniform 0;
     }
+
     frontAndBack
     {
         type            empty;
     }
+
+    ".*"
+    {
+        type            calculated;
+        value           $internalField;
+    }
 }
 
 

tutorials/incompressible/simpleFoam/simpleCar/0/p

@@ -20,26 +20,22 @@ internalField   uniform 0;
 
 boundaryField
 {
-    inlet
-    {
-        type            zeroGradient;
-    }
-
     outlet
     {
         type            fixedValue;
-        value           uniform 0;
+        value           $internalField;
-    }
-
-    "(body|upperWall|lowerWall)"
-    {
-        type            zeroGradient;
     }
 
     frontAndBack
     {
         type            empty;
     }
+
+    ".*"
+    {
+        type            zeroGradient;
+    }
+
 }
 
 // ************************************************************************* //

tutorials/incompressible/simpleFoam/simpleCar/Allrun

@@ -4,6 +4,7 @@ cd ${0%/*} || exit 1                        # Run from this directory
 
 runApplication blockMesh
 runApplication topoSet
+runApplication createPatch -overwrite
 runApplication $(getApplication)
 
 #------------------------------------------------------------------------------

tutorials/incompressible/simpleFoam/simpleCar/system/createPatchDict

@@ -0,0 +1,43 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+| =========                 |                                                 |
+| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
+|  \\    /   O peration     | Version:  v1906                                 |
+|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
+|    \\/     M anipulation  |                                                 |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      createPatchDict;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+pointSync false;
+
+// Patches to create
+patches
+(
+    {
+        // Name of new patch
+        name airIntake;
+
+        // Dictionary to construct new patch from
+        patchInfo
+        {
+            type patch;
+        }
+
+        // How to construct: either from 'patches' or 'set'
+        constructFrom set;
+
+        // If constructFrom = patches : names of patches. Wildcards allowed.
+        patches ();
+
+        // If constructFrom = set : name of faceSet
+        set airIntake;
+    }
+);
+
+// ************************************************************************* //

tutorials/incompressible/simpleFoam/simpleCar/system/topoSetDict

@@ -31,6 +31,23 @@ actions
         source  setToCellZone;
         set     porousCells;
     }
+
+    {
+        name    airIntake;
+        type    faceSet;
+        action  new;
+        source  patchToFace;
+        patch   body;
+    }
+    {
+        name    airIntake;
+        type    faceSet;
+        action  subset;
+        source  boxToFace;
+        box     (2.6 0.75 0)(2.64 0.8 0.1);
+    }
+
+
 );
 
 // ************************************************************************* //