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-   -   Calculating moment of inertia of a NACA-0012 wing for pitching motion (https://www.cfd-online.com/Forums/openfoam-solving/225493-calculating-moment-inertia-naca-0012-wing-pitching-motion.html)

Rohan123 March 28, 2020 10:06

Calculating moment of inertia of a NACA-0012 wing for pitching motion
 
Hey, so I am trying to simulate the pitching motion of a NACA-0012 wing and I went through the tutorial. I used 6-DOF rigidbodyofmotion solver. I am unable to accurately determine the moment of inertia of the wing. Due to this, my angular velocity seems to blow up after a while.
Can anyone please help me with it?

13.6 gm wing with a chord length of 0.15m, span of 0.15m and the max thickness is 0.018m.
I want it to pitch (not plunge) from 0 to 18 degrees at 0.0314 rad/s.

I have added my dynamicMeshDict file for reference.
dynamicFvMesh dynamicMotionSolverFvMesh;

motionSolverLibs ("libsixDoFRigidBodyMotion.so");

solver sixDoFRigidBodyMotion;

sixDoFRigidBodyMotionCoeffs
{
patches (airfoil);
innerDistance 0.15;
outerDistance 0.3;

mass 0.0136;
centreOfMass (0.06024 0 0);
momentOfInertia (1.462e-4 0.892e-4 0.593e-2);


orientation
(
1 0 0
0 1 0
0 0 1
);
angularMomentum (0 1.96202e-05 0);
g (0 0 -9.81);
rho rhoInf;
rhoInf 1;
report on;

solver
{
type symplectic;
}

constraints
{
zLine
{
sixDoFRigidBodyMotionConstraint point;
centreOfRotation (0.0375 0 0);
direction (0 0 1);
}

yAxis
{
sixDoFRigidBodyMotionConstraint axis;
axis (0 1 0);
}
}

}
restraints
{
verticalSpring
{
sixDoFRigidBodyMotionRestraint linearSpring;

anchor (0.0375 0 0); // 1 or 0?
refAttachmentPt (0.0375 0 0);
stiffness 4000;
damping 2;
restLength 0;
}

axialSpring
{
sixDoFRigidBodyMotionRestraint linearAxialAngularSpring;

axis (0 1 0);
stiffness 700;
damping 0.5;


}

// ************************************************** *********************** //


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