Some questions about coordinates when using floating objects of chrono

de1ft · February 2022

Would you please consider the following questions about floating objects?

Q1:I want to change the coordinates of <floatings> section to define a new rotation axis instead of global coordinate. How to achieve it?

Q2: If I do the rotations (<rotateaxis>) applied to final position of particles in <initials> section as below:

I want know whether the following links are defined with global coordinates or rotated coordinates in <chrono> section ?

Thanks in advance for dealing with this.

@Alex

Asalih3d · February 2022

Hi

For Q2 you can test this easily by defining two bodies of interest you have and then trying to use both approaches, to see what physically makes sense. To my understanding <initials> happens before anything else simulation-wise, so you should use the locations in the global coordinate system for the rotated geometry. This is atleast my understanding.

For Q1 I am also interested in Alex' answer so will not dive to deep into it, since I don't think you can set x y z to something other than 0 and 1 in <floating>. What you can do instead is looking at DualSPHysics_v5.0\examples\others\ChronoPointline and see if the approach with Chronopointline can help in your case.

Kind regards

Alex · February 2022

Dear all

Let me tell you in advance that I am going to be 4 months on paternity leave, so I would not check this so often.

But I will try to reply when possible

Regards

Asalih3d · February 2022

https://forums.dual.sphysics.org/discussion/comment/4943#Comment_4943

That is great news! Hope you have a good time 😊

Kind regards

de1ft · February 2022

https://forums.dual.sphysics.org/discussion/comment/4940#Comment_4940

Thanks a lot for your answers.

For Q2, I followed your suggestion. It is proved that <chrono> section are still with global coordinates after doing rotaion.

For Q1, now the alternative way I choose now is to change the angular velocity of the motion to achieve a rotation that does not respect the axes of the global coordinate system.

de1ft · February 2022

https://forums.dual.sphysics.org/discussion/comment/4943#Comment_4943

Sorry to bother you at your holiday. And hope you have a nice experience!

xue · March 2022

Hi @de1ft,

Wish you all good!

I using Chrono to simulate rotation of blades in a stirred tank, do you know how can I make the blades rotate by itself. How to define the rotate axis for blades? I try to use motion to define, but motion part can not use in Chrono.

</angularvel>

</floatings>

Thanks for you time!

Best wishes,

Xue

Some questions about coordinates when using floating objects of chrono

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