rigidBodyDynamics: Added rotating joint

This joint allows two bodies to rotate relative to each other at a
specified speed. The relative motion is completely specified, so this
joint has zero degrees of freedom.

It could be used, for example, to attach a rotating propeller to a
moving ship:

    bodies
    {
        hull
        {
            ...
        }
        propeller
        {
            type            rigidBody;

            // Dynamic properties
            mass            ...;
            centreOfMass    ...;
            inertia         ...;

            // The propeller is connected to the hull
            parent          hull;

            // The position relative to the hull
            transform       (1 0 0 0 1 0 0 0 1) (20 0 0);

            // Rotation settings
            joint
            {
                type            rotating;
                omega           (6 0 0);
            }
        }
    }

applications/test/rigidBodyDynamics/doublePendulumAndRotor

@@ -0,0 +1,59 @@
+solver
+{
+    type symplectic;
+}
+
+bodies
+{
+    bar1
+    {
+        type            rigidBody;
+        mass            3;
+        centreOfMass    (0 -0.5 0);
+        inertia         (0.2575 0 0 0.015 0 0.2575);
+        parent          root;
+        transform       (1 0 0 0 1 0 0 0 1) (0 0 0);
+        joint
+        {
+            type            Rz;
+        }
+        outline         ((0 0 0) (0 -1 0));
+    }
+    bar2
+    {
+        type            rigidBody;
+        mass            3;
+        centreOfMass    (0 -0.5 0);
+        inertia         (0.2575 0 0 0.015 0 0.2575);
+        parent          bar1;
+        transform       (1 0 0 0 1 0 0 0 1) (0 -1 0);
+        joint
+        {
+            type            Rz;
+        }
+        outline         ((0 0 0) (0 -1 0));
+    }
+    rotor
+    {
+        type            rigidBody;
+        mass            3;
+        centreOfMass    (0 -0.5 0);
+        inertia         (0.2575 0 0 0.015 0 0.2575);
+        parent          bar2;
+        transform       (1 0 0 0 1 0 0 0 1) (0 -1 0);
+        joint
+        {
+            type            rotating;
+            omega           (0 0 1);
+        }
+        outline         ((0 0 0) (0 -1 0));
+    }
+}
+
+g (0 -9.81 0);
+
+q (1.5707963267948966 0 0);
+
+deltaT 0.01;
+
+endTime 20;

src/rigidBodyDynamics/Make/files

@@ -27,6 +27,7 @@ joints/Pa/Pa.C
 joints/Pxyz/Pxyz.C
 
 joints/rigid/rigid.C
+joints/rotating/rotating.C
 joints/function/function.C
 joints/functionDot/functionDot.C
 

src/rigidBodyDynamics/joints/rotating/rotating.C

@@ -0,0 +1,106 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2018-2022 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 "rotating.H"
+#include "rigidBodyModelState.H"
+#include "addToRunTimeSelectionTable.H"
+
+// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace RBD
+{
+namespace joints
+{
+    defineTypeNameAndDebug(rotating, 0);
+
+    addToRunTimeSelectionTable
+    (
+        joint,
+        rotating,
+        dictionary
+    );
+}
+}
+}
+
+
+// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
+
+Foam::RBD::joints::rotating::rotating
+(
+    const rigidBodyModel& model,
+    const dictionary& dict
+)
+:
+    joint(model, 0),
+    omega_(Function1<vector>::New("omega", dict))
+{}
+
+
+Foam::autoPtr<Foam::RBD::joint> Foam::RBD::joints::rotating::clone() const
+{
+    return autoPtr<joint>(new rotating(*this));
+}
+
+
+// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
+
+Foam::RBD::joints::rotating::~rotating()
+{}
+
+
+// * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //
+
+void Foam::RBD::joints::rotating::jcalc
+(
+    joint::XSvc& J,
+    const rigidBodyModelState& state
+) const
+{
+    const scalar t = state.t(), deltaT = state.deltaT();
+
+    if (t < vSmall || deltaT < vSmall)
+    {
+        return;
+    }
+
+    const vector omega = omega_->value(t);
+    const vector omegaDot = (omega - omega_->value(t - deltaT))/deltaT;
+    const vector theta = omega_->integral(0, t);
+    const scalar magTheta = mag(theta);
+    const tensor R =
+        magTheta > vSmall ? quaternion(theta, magTheta).R() : tensor::I;
+
+    J.X = spatialTransform(R, Zero);
+    J.S = Zero;
+    J.S1 = Zero;
+    J.v = spatialVector(omega, Zero);
+    J.c = - spatialVector(omegaDot, Zero);
+}
+
+
+// ************************************************************************* //

src/rigidBodyDynamics/joints/rotating/rotating.H

@@ -0,0 +1,114 @@
+/*---------------------------------------------------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Copyright (C) 2018-2022 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::RBD::joints::rotating
+
+Description
+    Joint with a specified rotational speed
+
+    Reference:
+    \verbatim
+        Featherstone, R. (2008).
+        Rigid body dynamics algorithms.
+        Springer.
+        Chapter 4.
+    \endverbatim
+
+SourceFiles
+    rotating.C
+
+\*---------------------------------------------------------------------------*/
+
+#ifndef RBD_joints_rotating_H
+#define RBD_joints_rotating_H
+
+#include "joint.H"
+#include "Function1.H"
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+namespace Foam
+{
+namespace RBD
+{
+namespace joints
+{
+
+/*---------------------------------------------------------------------------*\
+                         Class rotating Declaration
+\*---------------------------------------------------------------------------*/
+
+class rotating
+:
+    public joint
+{
+private:
+
+    // Private data
+
+        //- Rotation vector function
+        autoPtr<Function1<vector>> omega_;
+
+
+public:
+
+    //- Runtime type information
+    TypeName("rotating");
+
+
+    // Constructors
+
+        //- Construct for given model from dictionary
+        rotating(const rigidBodyModel& model, const dictionary& dict);
+
+        //- Clone this joint
+        virtual autoPtr<joint> clone() const;
+
+
+    //- Destructor
+    virtual ~rotating();
+
+
+    // Member Functions
+
+        //- Update the model state for this joint
+        virtual void jcalc
+        (
+            joint::XSvc& J,
+            const rigidBodyModelState& state
+        ) const;
+};
+
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+} // End namespace joints
+} // End namespace RBD
+} // End namespace Foam
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+#endif
+
+// ************************************************************************* //