ENH: FO: Lamb vector

- If applied:
      This commit allows the user to compute:
        - the Lamb vector (https://en.wikipedia.org/wiki/Lamb_vector),
        - on-the-fly or via postProcess utility
        - for a given volVectorField (one per functionObject entry)

  - Why:
      The motivation is the literature-reported quantitative connection
      between the Lamb vector (divergence) and the spatially localised
      instantaneous fluid motions, e.g. high- and low-momentum fluid
      parcels, which possess considerable level of capacity to affect
      the rate of change of momentum, and to generate forces such as drag.

  - Verification:
      - Smooth-wall plane channel flow case (Moser et al. 1999) by
          # Curtis et al. (2008) On the Lamb vector divergence
            in Navier–Stokes flows, doi:10.1017/S0022112008002760

  - What's next:
      - The verification-show case
      - Extended code guide entry titled "Lamb vector"

src/functionObjects/field/Make/files

@@ -60,6 +60,7 @@ ddt/ddt.C
 mag/mag.C
 magSqr/magSqr.C
 vorticity/vorticity.C
+lambVector/lambVector.C
 enstrophy/enstrophy.C
 Q/Q.C
 Lambda2/Lambda2.C

src/functionObjects/field/lambVector/lambVector.C

@@ -0,0 +1,70 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  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 "lambVector.H"
+#include "fvcCurl.H"
+#include "fvcDiv.H"
+#include "addToRunTimeSelectionTable.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace functionObjects
+{
+    defineTypeNameAndDebug(lambVector, 0);
+    addToRunTimeSelectionTable(functionObject, lambVector, dictionary);
+}
+}
+
+// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
+
+bool Foam::functionObjects::lambVector::calc()
+{
+    if (foundObject<volVectorField>(fieldName_))
+    {
+        const volVectorField& U = lookupObject<volVectorField>(fieldName_);
+        return store(resultName_, fvc::curl(U)^U);
+    }
+
+    return false;
+}
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::functionObjects::lambVector::lambVector
+(
+    const word& name,
+    const Time& runTime,
+    const dictionary& dict
+)
+:
+    fieldExpression(name, runTime, dict, "U")
+{
+    setResultName(typeName, fieldName_);
+}
+
+// ************************************************************************* //

src/functionObjects/field/lambVector/lambVector.H

@@ -0,0 +1,121 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  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::functionObjects::lambVector
+
+Group
+    grpFieldFunctionObjects
+
+Description
+    Calculates Lamb vector, i.e. the cross product of vorticity and velocity.
+    Calculation of the divergence of the Lamb vector can be performed by using
+    'div' functionObject on this 'lambVector' functionObject.
+
+    The field is stored on the mesh database so that it can be retrieved
+    and used for other applications.
+
+Usage
+    \verbatim
+    lambVector1
+    {
+        type        lambVector;
+        libs        ("libfieldFunctionObjects.so");
+        field       UMean;
+        ... Base options of fieldExpression ...
+    }
+    \endverbatim
+
+    Where the entries comprise:
+    \table
+        Property     | Description             | Required    | Default value
+        type         | Type name: lambVector   | yes         |
+        field        | Name of volVectorField  | no          | U
+    \endtable
+
+See also
+    Foam::functionObjects::fieldExpression
+
+SourceFiles
+    lambVector.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef functionObjects_lambVector_H
+#define functionObjects_lambVector_H
+
+#include "fieldExpression.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace functionObjects
+{
+
+/*---------------------------------------------------------------------------*\
+                          Class lambVector Declaration
+\*---------------------------------------------------------------------------*/
+
+class lambVector
+:
+    public fieldExpression
+{
+    // Private Member Functions
+
+        //- Calculate the lambVector field and return true if successful
+        virtual bool calc();
+
+
+public:
+
+    //- Runtime type information
+    TypeName("lambVector");
+
+
+    // Constructors
+
+        //- Construct from Time and dictionary
+        lambVector
+        (
+            const word& name,
+            const Time& runTime,
+            const dictionary& dict
+        );
+
+
+    //- Destructor
+    virtual ~lambVector() = default;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace functionObjects
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //