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

[Owen Hickey]

Hey all,

I think the easiest solution if you still want to use OIF is to simply
use the reuse_forces flag when calling integrate since the old forces
should still be correct in this case. Another option might be the COM
Virtual Sites, although I must concede I have no idea if it would
work.

Owen


On Tue, May 26, 2015 at 9:38 PM, Ivan Cimrak <address@hidden> wrote:
> 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
>>
>> _________________________________________________________
>>
>> Fraunhofer ICT-IMM
>>
>> Gruppe Modellierung / Modeling Group
>>
>> Abteilung Zukunftstechnologien / Future Technologies Department
>>
>> Carl-Zeiss-Straße 18-20, 55129 Mainz, Germany
>>
>> Phone +49 6131 990-396/ Fax +49 6131 990-205 / Mobile +49 1577-5327027
>>
>> address@hidden / www.imm.fraunhofer.de
>>
>
> --
> 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
>