Slerp for forced motion
 

Hi all,

I'm currently looking at the possibilities to use that neat little feature called Slerp, in the case of simple forced motion, rather than in sixDoFRigidBodyMotion/rigidBodyDynamics frameworks, which solve the dynamics of the system.

This mesh deformation solver appeared in OF 2.3, and is supposedly similar to RBF.

This should be easy since forced motion is simpler than solved motion, but the class using it are quite different from classic forced motion classes, mainly in fvMotionSolver... The best option would be to be able to access 'slerp' from the solver option in dynamicMeshDict.

Has anybody tried it ? Is it worth spending time on it ?

Thank you all for your help.

Hello,

I though about this before (when OF2.3 was released) and even stared to implement a blueprint for this case but I could not find enough time.
Let me tell you what I found (as I remember)

• ``sixDoFRigidBodyMotionSolver`` has a data member of type
  ``sixDoFRigidBodyMotion`` called motion_. That means it is designed to work with ``sixDoFRigidBody`` only.
• The main issue which makes this implementation is not ideal (easy) to generalize, it the fact that the scale of the motion and mesh update are done in the ``sixDoFRigidBodyMotionSolver`` class but the interpolation is done in ``sixDoFRigidBodyMotion``
• SLERP interpolation is implemented in separate class, which means it could be used to implement a new solver to satisfy your needs.
• SLERP interpolation class constructors require the motion to be descried by a vector and/or quaternion.

This is based on OF-2.3, this library has been changed in the recent versions. I hope my notes are useful for you.

Best wishes,
Hassan Kassem

Thanks a lot for your help Hassan. I'll keep you updated if I manage to move forward.

Ben

Hi all,


In case anyone is wondering, forced motions with slerp has been added to OpenFOAM 7 with interpolatingSolidBodyMotionSolver.


https://openfoam.org/release/7/


https://github.com/OpenFOAM/OpenFOAM...98ee933b910741