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-   -   axis of rotation for gen6DoF option (https://www.cfd-online.com/Forums/openfoam-solving/163519-axis-rotation-gen6dof-option.html)

hydraulist November 30, 2015 08:27
axis of rotation for gen6DoF option
 
Hi,

I apologize for another separate post on gen6DoF, since i couldn't get any replies i've made this thread.
Could anyone tell me about the default axis of rotational oscillation in gen6DoF application? Is it the CofG (Center of gravity) or the axis can be some arbitrary point outside the body. I'm working on liquid sloshing in a tank and interested to give rotation of tank about some arbitrary point. What could be done if i want to change the axis of rotation of a tank? Thanking you

wouter November 30, 2015 17:45
Hello hydraulist,
I think the answer is in
...../OpenFOAM/OpenFOAM-3.0.x/src/sixDoFRigidBodyMotion/sixDoFRigidBodyMotion
where it says that the momentum is calculated based on the axis
Code:
          // Moments are returned in global axes, transforming to
            // body local to add to torque.
            tau() += Q().T() & (rM + ((rP - centreOfRotation()) ^ rF));
hope this helps,
Wouter

hydraulist December 5, 2015 01:36
Hello Wouter,
Thank you for the reply. I'l try to understand and use that.


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