Motion constraints in sixDOFqODE

src/ODE/sixDOF/finiteRotation/finiteRotation.C

@@ -1,9 +1,9 @@
 /*---------------------------------------------------------------------------*\
   =========                 |
   \\      /  F ield         | foam-extend: Open Source CFD
-   \\    /   O peration     | Version:     3.2
+   \\    /   O peration     |
-    \\  /    A nd           | Web:         http://www.foam-extend.org
+    \\  /    A nd           | For copyright notice see file Copyright
-     \\/     M anipulation  | For copyright notice see file Copyright
+     \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
     This file is part of foam-extend.
@@ -72,7 +72,7 @@ Foam::scalar Foam::finiteRotation::rotAngle(const tensor& rotT)
 
 Foam::vector Foam::finiteRotation::eulerAngles(const tensor& rotT)
 {
-    // Define a vector containing euler angles (x = roll, y = pitch, z = yaw)
+    // Create a vector containing euler angles (x = roll, y = pitch, z = yaw)
     vector eulerAngles;
 
     scalar& rollAngle = eulerAngles.x();

src/ODE/sixDOF/finiteRotation/finiteRotation.H

@@ -1,9 +1,9 @@
 /*---------------------------------------------------------------------------*\
   =========                 |
   \\      /  F ield         | foam-extend: Open Source CFD
-   \\    /   O peration     | Version:     3.2
+   \\    /   O peration     |
-    \\  /    A nd           | Web:         http://www.foam-extend.org
+    \\  /    A nd           | For copyright notice see file Copyright
-     \\/     M anipulation  | For copyright notice see file Copyright
+     \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
     This file is part of foam-extend.
@@ -69,7 +69,7 @@ class finiteRotation
         //- Calculate rotation angle from given rotation tensor
         static scalar rotAngle(const tensor& rotT);
 
-        //- Calculate Euler angles (x-y-z (roll-pitch-yaw) convenction) from
+        //- Calculate Euler angles (x-y-z (roll-pitch-yaw) convention) from
         //  given rotation tensor. Reference: Mike Day, Insomniac Games,
         //  Extracting Euler Angles from a Rotation Matrix.
         static vector eulerAngles(const tensor& rotT);

src/ODE/sixDOF/sixDOFqODE/sixDOFqODE.C

@@ -118,11 +118,14 @@ Foam::dimensionedVector Foam::sixDOFqODE::E
 Foam::sixDOFqODE::sixDOFqODE(const IOobject& io)
 :
     IOdictionary(io),
+
     mass_(lookup("mass")),
     momentOfInertia_(lookup("momentOfInertia")),
+
     Xequilibrium_(lookup("equilibriumPosition")),
     linSpringCoeffs_(lookup("linearSpring")),
     linDampingCoeffs_(lookup("linearDamping")),
+
     Xrel_(lookup("Xrel")),
     U_(lookup("U")),
     Uaverage_(U_),
@@ -134,11 +137,20 @@ Foam::sixDOFqODE::sixDOFqODE(const IOobject& io)
     omega_(lookup("omega")),
     omegaAverage_(omega_),
     omegaAverageAbsolute_(omega_),
+
     force_(lookup("force")),
     moment_(lookup("moment")),
     forceRelative_(lookup("forceRelative")),
     momentRelative_(lookup("momentRelative")),
-    coeffs_(13, 0.0)
+
+    coeffs_(13, 0.0),
+
+    fixedSurge_(lookup("fixedSurge")),
+    fixedSway_(lookup("fixedSway")),
+    fixedHeave_(lookup("fixedHeave")),
+    fixedRoll_(lookup("fixedRoll")),
+    fixedPitch_(lookup("fixedPitch")),
+    fixedYaw_(lookup("fixedYaw"))
 {
     setCoeffs();
 }
@@ -163,11 +175,14 @@ Foam::sixDOFqODE::sixDOFqODE
             IOobject::NO_WRITE
         )
     ),
+
     mass_(sd.mass_.name(), sd.mass_),
     momentOfInertia_(sd.momentOfInertia_.name(), sd.momentOfInertia_),
+
     Xequilibrium_(sd.Xequilibrium_.name(), sd.Xequilibrium_),
     linSpringCoeffs_(sd.linSpringCoeffs_.name(), sd.linSpringCoeffs_),
     linDampingCoeffs_(sd.linDampingCoeffs_.name(), sd.linDampingCoeffs_),
+
     Xrel_(sd.Xrel_.name(), sd.Xrel_),
     U_(sd.U_.name(), sd.U_),
     Uaverage_(sd.Uaverage_.name(), sd.Uaverage_),
@@ -179,11 +194,20 @@ Foam::sixDOFqODE::sixDOFqODE
         sd.omegaAverageAbsolute_.name(),
         sd.omegaAverageAbsolute_
     ),
+
     force_(sd.force_.name(), sd.force_),
     moment_(sd.moment_.name(), sd.moment_),
     forceRelative_(sd.forceRelative_.name(), sd.forceRelative_),
     momentRelative_(sd.momentRelative_.name(), sd.momentRelative_),
-    coeffs_(sd.coeffs_)
+
+    coeffs_(sd.coeffs_),
+
+    fixedSurge_(sd.fixedSurge_),
+    fixedSway_(sd.fixedSway_),
+    fixedHeave_(sd.fixedHeave_),
+    fixedRoll_(sd.fixedRoll_),
+    fixedPitch_(sd.fixedPitch_),
+    fixedYaw_(sd.fixedYaw_)
 {}
 
 
@@ -199,9 +223,11 @@ void Foam::sixDOFqODE::setState(const sixDOFqODE& sd)
 {
     mass_ = sd.mass_;
     momentOfInertia_ = sd.momentOfInertia_;
+
     Xequilibrium_ = sd.Xequilibrium_;
     linSpringCoeffs_ = sd.linSpringCoeffs_;
     linDampingCoeffs_ = sd.linDampingCoeffs_;
+
     Xrel_ = sd.Xrel_;
     U_ = sd.U_;
     Uaverage_ = sd.Uaverage_;
@@ -209,6 +235,7 @@ void Foam::sixDOFqODE::setState(const sixDOFqODE& sd)
     omega_ = sd.omega_;
     omegaAverage_ = sd.omegaAverage_;
     omegaAverageAbsolute_ = sd.omegaAverageAbsolute_;
+
     force_ = sd.force_;
     moment_ = sd.moment_;
     forceRelative_ = sd.forceRelative_;
@@ -217,6 +244,13 @@ void Foam::sixDOFqODE::setState(const sixDOFqODE& sd)
     // Copy ODE coefficients: this carries actual ODE state
     // HJ, 23/Mar/2015
     coeffs_ = sd.coeffs_;
+
+    fixedSurge_ = sd.fixedSurge_;
+    fixedSway_ = sd.fixedSway_;
+    fixedHeave_ = sd.fixedHeave_;
+    fixedRoll_ = sd.fixedRoll_;
+    fixedPitch_ = sd.fixedPitch_;
+    fixedYaw_ = sd.fixedYaw_;
 }
 
 
@@ -248,6 +282,23 @@ void Foam::sixDOFqODE::derivatives
     dydx[4] = accel.y();
     dydx[5] = accel.z();
 
+    // Add translational constraints by setting RHS of given components to zero
+    if (fixedSurge_)
+    {
+        dydx[0] = 0; // Surge velocity
+        dydx[3] = 0; // Surge acceleration
+    }
+    if (fixedSway_)
+    {
+        dydx[1] = 0; // Sway velocity
+        dydx[4] = 0; // Sway acceleration
+    }
+    if (fixedHeave_)
+    {
+        dydx[2] = 0; // Heave velocity
+        dydx[5] = 0; // Heave acceleration
+    }
+
     // Set the derivatives for rotation
     dimensionedVector curOmega
     (
@@ -266,6 +317,23 @@ void Foam::sixDOFqODE::derivatives
     dydx[10] = curRotation.eDot(curOmega.value(), 1);
     dydx[11] = curRotation.eDot(curOmega.value(), 2);
     dydx[12] = curRotation.eDot(curOmega.value(), 3);
+
+    // Add rotational constraints by setting RHS of given components to zero
+    if (fixedRoll_)
+    {
+        dydx[6] = 0; // Roll angular acceleration
+        dydx[10] = 0; // Roll angular velocity (roll quaternion evolution RHS)
+    }
+    if (fixedPitch_)
+    {
+        dydx[7] = 0; // Pitch angular acceleration
+        dydx[11] = 0; // Pitch angular velocity (pitch quaternion evolution RHS)
+    }
+    if (fixedYaw_)
+    {
+        dydx[8] = 0; // Yaw angular acceleration
+        dydx[12] = 0; // Yaw angular velocity (yaw quaternion evolution RHS)
+    }
 }
 
 
@@ -367,6 +435,19 @@ Foam::Ostream& Foam::operator<<(Ostream& os, const sixDOFqODE& sds)
     os.writeKeyword("momentRelative") << tab << sds.momentRelative()
         << token::END_STATEMENT << endl;
 
+    os.writeKeyword("fixedSurge") << tab << sds.fixedSurge_ <<
+        token::END_STATEMENT << endl;
+    os.writeKeyword("fixedSway") << tab << sds.fixedSway_ <<
+        token::END_STATEMENT << endl;
+    os.writeKeyword("fixedHeave") << tab << sds.fixedHeave_ <<
+        token::END_STATEMENT << endl;
+    os.writeKeyword("fixedRoll") << tab << sds.fixedRoll_ <<
+        token::END_STATEMENT << endl;
+    os.writeKeyword("fixedPitch") << tab << sds.fixedPitch_ <<
+        token::END_STATEMENT << endl;
+    os.writeKeyword("fixedYaw") << tab << sds.fixedYaw_ <<
+        token::END_STATEMENT << endl;
+
     return os;
 }
 

src/ODE/sixDOF/sixDOFqODE/sixDOFqODE.H

@@ -131,6 +131,27 @@ class sixDOFqODE
         scalarField coeffs_;
 
 
+        //- Motion constraints (given as fixed motion components)
+
+            //- Fixed surge (x-translation)
+            Switch fixedSurge_;
+
+            //- Fixed sway (y-translation)
+            Switch fixedSway_;
+
+            //- Fixed heave (z-translation)
+            Switch fixedHeave_;
+
+            //- Fixed roll (rotation around x)
+            Switch fixedRoll_;
+
+            //- Fixed pitch (rotation around y)
+            Switch fixedPitch_;
+
+            //- Fixed yaw (rotation around z)
+            Switch fixedYaw_;
+
+
     // Private Member Functions
 
         //- Disallow default bitwise copy construct

tutorials/basic/sixDOFSolver/sixDOFmotion/0/bodyA

@@ -36,4 +36,12 @@ moment              m           [1 2 -2 0 0 0 0]     (0 0 0);
 forceRelative       fRel        [1 1 -2 0 0 0 0]     (0 0 0);
 momentRelative      mRel        [1 2 -2 0 0 0 0]     (-0.5773502692 -0.5773502692 -0.5773502692);
 
+// Motion constraints
+fixedSurge          no;
+fixedSway           no;
+fixedHeave          no;
+fixedRoll           no;
+fixedPitch          no;
+fixedYaw            no;
+
 // ************************************************************************* //

tutorials/basic/sixDOFSolver/sixDOFmotion/0/bodyB

@@ -35,4 +35,12 @@ moment              m           [1 2 -2 0 0 0 0]     (0 0 0);
 forceRelative       fRel        [1 1 -2 0 0 0 0]     (0 0 0);
 momentRelative      mRel        [1 2 -2 0 0 0 0]     (0 0 10);
 
+// Motion constraints
+fixedSurge          no;
+fixedSway           no;
+fixedHeave          no;
+fixedRoll           no;
+fixedPitch          no;
+fixedYaw            no;
+
 // ************************************************************************* //

tutorials/basic/sixDOFSolver/springDamper/0/massSpringDamper

@@ -35,4 +35,13 @@ moment              m           [1 2 -2 0 0 0 0]     (0 0 0);
 forceRelative       fRel        [1 1 -2 0 0 0 0]     (0 0 0);
 momentRelative      mRel        [1 2 -2 0 0 0 0]     (0 0 0);
 
+
+// Motion constraints
+fixedSurge          no;
+fixedSway           no;
+fixedHeave          no;
+fixedRoll           no;
+fixedPitch          no;
+fixedYaw            no;
+
 // ************************************************************************* //