functionObjects::cylindricalFunctionObject: New functionObject to transform velocity into cylindrical polar coordinates

Description
    Transforms the specified velocity field into a
    cylindrical polar coordinate system or back to Cartesian.

    Example of function object specification to convert the velocity field U
    into cylindrical polar coordinates before averaging and returning the
    average to Cartesian coordinates:
    \verbatim
    cartesianToCylindrical
    {
        type        cylindrical;
        libs        ("libfieldFunctionObjects.so");

        origin      (0 0 0);
        axis        (0 0 1);

        field       U;

        writeControl    outputTime;
        writeInterval   1;
    }

    #includeFunc fieldAverage(cylindrical(U))

    cylindricalToCartesian
    {
        type        cylindrical;
        libs        ("libfieldFunctionObjects.so");

        origin      (0 0 0);
        axis        (0 0 1);

        field       cylindrical(U)Mean;
        toCartesian true;
        result      UMean;

        writeControl    outputTime;
        writeInterval   1;
    }
    \endverbatim
    This is particularly useful for cases with rotating regions, e.g. mixer
    vessels with AMI.

See tutorials/incompressible/pimpleFoam/laminar/mixerVesselAMI2D

src/functionObjects/field/Make/files

@@ -76,4 +76,6 @@ age/age.C
 
 comfort/comfort.C
 
+cylindrical/cylindricalFunctionObject.C
+
 LIB = $(FOAM_LIBBIN)/libfieldFunctionObjects

src/functionObjects/field/cylindrical/cylindricalFunctionObject.C

@@ -0,0 +1,149 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2020 OpenFOAM Foundation
+     \\/     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 "cylindricalFunctionObject.H"
+#include "volFields.H"
+#include "addToRunTimeSelectionTable.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace functionObjects
+{
+    defineTypeNameAndDebug(cylindrical, 0);
+
+    addToRunTimeSelectionTable
+    (
+        functionObject,
+        cylindrical,
+        dictionary
+    );
+}
+}
+
+
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+Foam::tensor Foam::functionObjects::cylindrical::R(const vector& p) const
+{
+    vector dir = p - origin_;
+    dir /= mag(dir) + vSmall;
+
+    const vector axis = axis_/mag(axis_);
+    const vector r = dir - (dir & axis)*axis;
+
+    return tensor(r, axis^r, axis);
+}
+
+
+void Foam::functionObjects::cylindrical::transform
+(
+    vectorField& vf,
+    const vectorField& points
+) const
+{
+    if (toCartesian_)
+    {
+        forAll(points, i)
+        {
+            vf[i] = this->R(points[i]).T() & vf[i];
+        }
+    }
+    else
+    {
+        forAll(points, i)
+        {
+            vf[i] = this->R(points[i]) & vf[i];
+        }
+    }
+}
+
+
+bool Foam::functionObjects::cylindrical::calc()
+{
+    if (foundObject<volVectorField>(fieldName_))
+    {
+        const volVectorField& vf = lookupObject<volVectorField>(fieldName_);
+        const volVectorField& C = mesh_.C();
+
+        tmp<volVectorField> tcvf(volVectorField::New(resultName_, vf));
+
+        volVectorField& cvf = tcvf.ref();
+        transform(cvf.primitiveFieldRef(), C);
+
+        forAll(vf.boundaryField(), patchi)
+        {
+            transform
+            (
+                cvf.boundaryFieldRef()[patchi],
+                C.boundaryField()[patchi]
+            );
+        }
+
+        return store(resultName_, tcvf);
+    }
+    else
+    {
+        cannotFindObject<volVectorField>(fieldName_);
+
+        return false;
+    }
+
+    return true;
+}
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::functionObjects::cylindrical::cylindrical
+(
+    const word& name,
+    const Time& runTime,
+    const dictionary& dict
+)
+:
+    fieldExpression
+    (
+        name,
+        runTime,
+        dict,
+        dict.lookupOrDefault<Switch>("toCartesian", false)
+      ? "cartesian"
+      : typeName
+    ),
+    origin_(dict.lookup("origin")),
+    axis_(dict.lookup("axis")),
+    toCartesian_(dict.lookupOrDefault<Switch>("toCartesian", false))
+{}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::functionObjects::cylindrical::~cylindrical()
+{}
+
+
+// ************************************************************************* //

src/functionObjects/field/cylindrical/cylindricalFunctionObject.H

@@ -0,0 +1,150 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2020 OpenFOAM Foundation
+     \\/     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::functionObjects::cylindrical
+
+Description
+    Transforms the specified velocity field into a
+    cylindrical polar coordinate system or back to Cartesian.
+
+    Example of function object specification to convert the velocity field U
+    into cylindrical polar coordinates before averaging and returning the
+    average to Cartesian coordinates:
+    \verbatim
+    cartesianToCylindrical
+    {
+        type        cylindrical;
+        libs        ("libfieldFunctionObjects.so");
+
+        origin      (0 0 0);
+        axis        (0 0 1);
+
+        field       U;
+
+        writeControl    outputTime;
+        writeInterval   1;
+    }
+
+    #includeFunc fieldAverage(cylindrical(U))
+
+    cylindricalToCartesian
+    {
+        type        cylindrical;
+        libs        ("libfieldFunctionObjects.so");
+
+        origin      (0 0 0);
+        axis        (0 0 1);
+
+        field       cylindrical(U)Mean;
+        toCartesian true;
+        result      UMean;
+
+        writeControl    outputTime;
+        writeInterval   1;
+    }
+    \endverbatim
+    This is particularly useful for cases with rotating regions, e.g. mixer
+    vessels with AMI.
+
+See also
+    Foam::functionObjects::fieldExpression
+    Foam::functionObjects::fvMeshFunctionObject
+
+SourceFiles
+    cylindrical.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef cylindricalFunctionObject_H
+#define cylindricalFunctionObject_H
+
+#include "fieldExpression.H"
+#include "primitiveFieldsFwd.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace functionObjects
+{
+
+/*---------------------------------------------------------------------------*\
+                          Class cylindrical Declaration
+\*---------------------------------------------------------------------------*/
+
+class cylindrical
+:
+    public fieldExpression
+{
+    // Private Data
+
+        vector origin_;
+
+        vector axis_;
+
+
+    // Private Member Functions
+
+        tensor R(const vector& p) const;
+
+        void transform(vectorField& vf, const vectorField& points) const;
+
+        bool toCartesian_;
+
+        //- Calculate the cylindrical field and return true if successful
+        virtual bool calc();
+
+
+public:
+
+    //- Runtime type information
+    TypeName("cylindrical");
+
+
+    // Constructors
+
+        //- Construct from Time and dictionary
+        cylindrical
+        (
+            const word& name,
+            const Time& runTime,
+            const dictionary& dict
+        );
+
+
+    //- Destructor
+    virtual ~cylindrical();
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace functionObjects
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

tutorials/incompressible/pimpleFoam/laminar/mixerVesselAMI2D/system/controlDict

@@ -29,7 +29,7 @@ deltaT          1e-3;
 
 writeControl    adjustableRunTime;
 
-writeInterval   0.1;
+writeInterval   0.05;
 
 purgeWrite      0;
 
@@ -49,4 +49,40 @@ adjustTimeStep  yes;
 
 maxCo           0.5;
 
+functions
+{
+    cartesianToCylindrical
+    {
+        type        cylindrical;
+        libs        ("libfieldFunctionObjects.so");
+
+        origin      (0 0 0);
+        axis        (0 0 1);
+
+        field       U;
+
+        writeControl    outputTime;
+        writeInterval   1;
+    }
+
+    #includeFunc fieldAverage(cylindrical(U))
+
+    cylindricalToCartesian
+    {
+        type        cylindrical;
+        libs        ("libfieldFunctionObjects.so");
+
+        origin      (0 0 0);
+        axis        (0 0 1);
+
+        field       cylindrical(U)Mean;
+        toCartesian true;
+        result      UMean;
+
+        writeControl    outputTime;
+        writeInterval   1;
+    }
+}
+
+
 // ************************************************************************* //