Re: [ESPResSo-users] fixing an object in a fluid than only rotates

[Ivan Cimrak]

Dear Lena,

Currently, there is no such functionality. Also, I can't see right now
any way how to keeps let's say a centroid of the object fixed. The
option of moving the centroid of the object always back is of course
possible, but this way, you get the recalculating the forces, because
the positions of the particles are being set.

If you want to simulate rigid objects, virtual sites are maybe an
option, however, this is not within the OIF module.

I wonder what is the reason to have such feature. If you want to
simulate couette flow and you want your object to be almost at one
place, just with rotation, initiate the couette flow by moving the
upper wall to the right and bottom wall to the left, both with halved
velocities.

I hope this helps,
Ivan




Dňa 26.5.2015 o 15:32 Holst, Lena napísal(a):
> Hello,
>
> I want to create an sphere object in a couette-flow. The object should
> only be able to rotate, but fixed at one position. When I set the origin
> of the object at each integrationstep at the same position, every
> integration it comes the message “Recalculated forces, so the LB
> coupling forces are not included in the particle force the first time
> step.” So, I think this way is not very useful. Is there any other way
> to fix the object at one defined position, so that this is only able to
> rotate through the force of the fluid?
>
> Best regards and a lot of thanks for effort,
>
> Lena Holst
>
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-- 
Ivan Cimrak
FRI Zilinska Univerzita v Ziline
personal web: http://www.kst.fri.uniza.sk/~icimrak/
cell-in-fluid group: http://cell-in-fluid.fri.uniza.sk