wallDist/patchDistMethods/Poisson: New method for fast calculation of an approximate wall-distance field

by solving Poisson's equation

src/finiteVolume/Make/files

@@ -44,6 +44,7 @@ $(wallDist)/nearWallDist/nearWallDist.C
 $(wallDist)/wallDist/wallDist.C
 $(wallDist)/patchDistMethods/patchDistMethod/patchDistMethod.C
 $(wallDist)/patchDistMethods/meshWave/meshWavePatchDistMethod.C
+$(wallDist)/patchDistMethods/Poisson/PoissonPatchDistMethod.C
 
 
 fvMeshMapper = fvMesh/fvMeshMapper

src/finiteVolume/fvMesh/wallDist/patchDistMethods/Poisson/PoissonPatchDistMethod.C

@@ -0,0 +1,129 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2015 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 "PoissonPatchDistMethod.H"
+#include "fvcGrad.H"
+#include "fvmLaplacian.H"
+#include "addToRunTimeSelectionTable.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace patchDistMethods
+{
+    defineTypeNameAndDebug(Poisson, 0);
+    addToRunTimeSelectionTable(patchDistMethod, Poisson, dictionary);
+}
+}
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::patchDistMethods::Poisson::Poisson
+(
+    const dictionary& dict,
+    const fvMesh& mesh,
+    const labelHashSet& patchIDs
+)
+:
+    patchDistMethod(mesh, patchIDs)
+{}
+
+
+Foam::patchDistMethods::Poisson::Poisson
+(
+    const fvMesh& mesh,
+    const labelHashSet& patchIDs
+)
+:
+    patchDistMethod(mesh, patchIDs)
+{}
+
+
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+bool Foam::patchDistMethods::Poisson::correct(volScalarField& y)
+{
+    return correct(y, const_cast<volVectorField&>(volVectorField::null()));
+}
+
+
+bool Foam::patchDistMethods::Poisson::correct
+(
+    volScalarField& y,
+    volVectorField& n
+)
+{
+    if (!tyPsi_.valid())
+    {
+        tyPsi_ = tmp<volScalarField>
+        (
+            new volScalarField
+            (
+                IOobject
+                (
+                    "yPsi",
+                    mesh_.time().timeName(),
+                    mesh_
+                ),
+                mesh_,
+                dimensionedScalar("yPsi", sqr(dimLength), 0.0),
+                y.boundaryField().types()
+            )
+        );
+    }
+
+    volScalarField& yPsi = tyPsi_();
+
+    solve(fvm::laplacian(yPsi) == dimensionedScalar("1", dimless, -1.0));
+
+    volVectorField gradyPsi(fvc::grad(yPsi));
+    volScalarField magGradyPsi(mag(gradyPsi));
+
+    y = sqrt(magSqr(gradyPsi) + 2*yPsi) - magGradyPsi;
+
+    // Cache yPsi if the mesh is moving otherwise delete
+    if (!mesh_.changing())
+    {
+        tyPsi_.clear();
+    }
+
+    // Only calculate n if the field is defined
+    if (notNull(n))
+    {
+        n =
+           -gradyPsi
+           /max
+            (
+                magGradyPsi,
+                dimensionedScalar("smallMagGradyPsi", dimLength, SMALL)
+            );
+    }
+
+    return true;
+}
+
+
+// ************************************************************************* //

src/finiteVolume/fvMesh/wallDist/patchDistMethods/Poisson/PoissonPatchDistMethod.H

@@ -0,0 +1,177 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Copyright (C) 2015 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::patchDistMethods::Poisson
+
+Description
+    Calculation of approximate distance to nearest patch for all cells and
+    boundary using a Poisson equation.
+
+    References:
+    \verbatim
+        D.B.Spalding,
+        "Calculation of turbulent heat transfer in cluttered spaces",
+        Proc. 10th Int. Heat Transfer Conference, Brighton, UK, (1994).
+
+        E.Fares and W.Schroder,
+        "Differential Equation for Approximate Wall Distance",
+        Int.J.Numer.Meth., 39:743-762, (2002).
+
+        P. G. Tucker,
+        "Differential equation based wall distance computation for DES and
+         RANS",
+        J.Comp.Phys., Vol. 190, Issue 1, 1 st September, pp. 229-248 (2003)
+    \endverbatim
+
+    Example of the wallDist specification in fvSchemes:
+    \verbatim
+        laplacianSchemes
+        {
+            .
+            .
+            laplacian(yPsi) Gauss linear corrected;
+            .
+            .
+        }
+
+        wallDist
+        {
+            method Poisson;
+        }
+    \endverbatim
+    Also the solver specification for yPsi is required in fvSolution, e.g.
+    for simple cases:
+    \verbatim
+        yPsi
+        {
+            solver          PCG;
+            preconditioner  DIC;
+            tolerance       1e-5;
+            relTol          0;
+        }
+
+    or for more complex cases:
+
+        yPsi
+        {
+            solver          GAMG;
+            smoother        GaussSeidel;
+            cacheAgglomeration true;
+            nCellsInCoarsestLevel 10;
+            agglomerator    faceAreaPair;
+            mergeLevels     1;
+            tolerance       1e-5;
+            relTol          0;
+        }
+    \endverbatim
+
+SeeAlso
+    Foam::patchDistMethod::meshWave
+    Foam::wallDist
+
+SourceFiles
+    PoissonPatchDistMethod.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef PoissonPatchDistMethod_H
+#define PoissonPatchDistMethod_H
+
+#include "patchDistMethod.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace patchDistMethods
+{
+
+/*---------------------------------------------------------------------------*\
+                          Class Poisson Declaration
+\*---------------------------------------------------------------------------*/
+
+class Poisson
+:
+    public patchDistMethod
+{
+    // Private Member Data
+
+        //- Cache yPsi for moving meshes
+        tmp<volScalarField> tyPsi_;
+
+
+    // Private Member Functions
+
+        //- Disallow default bitwise copy construct
+        Poisson(const Poisson&);
+
+        //- Disallow default bitwise assignment
+        void operatorconst Poisson&);
+
+
+public:
+
+    //- Runtime type information
+    TypeName("Poisson");
+
+
+    // Constructors
+
+        //- Construct from coefficients dictionary, mesh
+        //  and fixed-value patch set
+        Poisson
+        (
+            const dictionary& dict,
+            const fvMesh& mesh,
+            const labelHashSet& patchIDs
+        );
+
+        //- Construct from mesh and fixed-value patch set
+        Poisson
+        (
+            const fvMesh& mesh,
+            const labelHashSet& patchIDs
+        );
+
+
+    // Member Functions
+
+        //- Correct the given distance-to-patch field
+        virtual bool correct(volScalarField& y);
+
+        //- Correct the given distance-to-patch and normal-to-patch fields
+        virtual bool correct(volScalarField& y, volVectorField& n);
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace patchDistMethods
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //

src/finiteVolume/fvMesh/wallDist/patchDistMethods/meshWave/meshWavePatchDistMethod.C

@@ -75,6 +75,8 @@ Foam::patchDistMethods::meshWave::meshWave
 
 bool Foam::patchDistMethods::meshWave::correct(volScalarField& y)
 {
+    y = dimensionedScalar("yWall", dimLength, GREAT);
+
     // Calculate distance starting from patch faces
     patchWave wave(mesh_, patchIDs_, correctWalls_);
 
@@ -105,6 +107,8 @@ bool Foam::patchDistMethods::meshWave::correct
     volVectorField& n
 )
 {
+    y = dimensionedScalar("yWall", dimLength, GREAT);
+
     // Collect pointers to data on patches
     UPtrList<vectorField> patchData(mesh_.boundaryMesh().size());
 

src/finiteVolume/fvMesh/wallDist/patchDistMethods/meshWave/meshWavePatchDistMethod.H

@@ -22,21 +22,29 @@ License
     along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
 Class
-    Foam::patchDist
+    Foam::patchDistMethods::meshWave
 
 Description
-    Calculation of distance to nearest patch for all cells and boundary
+    Fast topological mesh-wave method for calculating the distance to nearest
-    using meshWave.
+    patch for all cells and boundary.
 
-    Distance correction (correctWalls = true):
+    For regular/un-distorted meshes this method is accurate but for skewed,
-        For each cell with face on wall calculate the true nearest point (by
+    non-orthogonal meshes it is approximate with the error increasing with the
-        triangle decomposition) on that face and do the same for that face's
+    degree of mesh distortion.  The distance from the near-wall cells to the
-        pointNeighbours. This will find the true nearest distance in almost all
+    boundary may optionally be corrected for mesh distortion by setting
-        cases. Only very skewed cells or cells close to another wall might be
+    correctWalls = true.
-        missed.
 
-        For each cell with only one point on wall the same is done except now it
+    Example of the wallDist specification in fvSchemes:
-        takes the pointFaces() of the wall point to look for the nearest point.
+    \verbatim
+        wallDist
+        {
+            method meshWave;
+        }
+    \endverbatim
+
+SeeAlso
+    Foam::patchDistMethod::Poisson
+    Foam::wallDist
 
 SourceFiles
     meshWavePatchDistMethod.C
@@ -89,8 +97,8 @@ public:
 
     // Constructors
 
-        //- Construct from mesh and flag whether or not to correct wall.
+        //- Construct from coefficients dictionary, mesh
-        //  Calculate for all cells.
+        //  and fixed-value patch set
         meshWave
         (
             const dictionary& dict,
@@ -98,7 +106,8 @@ public:
             const labelHashSet& patchIDs
         );
 
-        //- Construct from mesh and flag whether or not to correct wall.
+        //- Construct from mesh, fixed-value patch set and flag specifying
+        //  whether or not to correct wall.
         //  Calculate for all cells. correctWalls : correct wall (face&point)
         //  cells for correct distance, searching neighbours.
         meshWave

src/finiteVolume/fvMesh/wallDist/patchDistMethods/patchDistMethod/patchDistMethod.H

@@ -145,7 +145,7 @@ public:
         //- Correct the given distance-to-patch field
         virtual bool correct(volScalarField& y) = 0;
 
-        //- Correct the given distance-to-patch and reflection vector fields
+        //- Correct the given distance-to-patch and normal-to-patch fields
         virtual bool correct(volScalarField& y, volVectorField& n) = 0;
 };
 

src/finiteVolume/fvMesh/wallDist/wallDist/wallDist.C

@@ -79,7 +79,7 @@ Foam::wallDist::wallDist(const fvMesh& mesh)
             mesh
         ),
         mesh,
-        dimensionedScalar("yWall", dimLength, GREAT),
+        dimensionedScalar("yWall", dimLength, SMALL),
         patchTypes<scalar>(pdm_->patchIDs())
     ),
     n_(NULL)