Setting the angular velocity of atoms

Submitted by marketos on Wed, 10/05/2011 - 12:51

Hi,

Does anybody know- is there any way to set the angular velocities of atoms to a specific value?
For velocities I can use fix_move and from a quick check I did I cannot find any similar option in LIGGGHTS as the rotate keyword does something slightly different.

Will I have to extend fix_move?

Thanks,

George

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ckloss's picture

ckloss | Wed, 10/05/2011 - 12:59

Hi george,

you can use the set command with keywords 'omegax', 'omegay' and 'omegaz' - see the doc for details.

Cheers, Christoph

marketos | Wed, 10/05/2011 - 13:19

Hi Christoph,

Sorry I did not explain well what I wanted to do- I want to keep the angular velocity of a grain constant (eg 0) throughout a run so that it does not get updated. I think set will only initiate the value but will then allow it to be updated.
Fix_move does what something similar for velocities, so I assume that I would need to modify it for angular velocitiies. But I wanted to check if this makes sense/ has already been done before I spend some time on coding.

Best wishes, George

ckloss's picture

ckloss | Wed, 10/05/2011 - 13:55

>> I want to keep the angular velocity of a grain constant (eg 0) throughout a run so that it does not get updated
You can do this by using the set command and then using fix nve instead of nve/sphere, so angular velocity will not be updated. But be careful when using pair gran with shear history, b/c shear history will be updated regardless of if you use nve or nve/sphere

Christoph