Dump drag forces of each particle.

Submitted by tshan on Wed, 04/06/2011 - 07:56

Hi Chris,

I feel sorry to disturb you, but I noticed that there are several comments in the input file of DEM:

#force : f_couple_cfd[0] f_couple_cfd[1] f_couple_cfd[2]
#node : f_couple_cfd[6]
#cell id : f_couple_cfd[7]

How do I output the drag forces and cell id of each particle together with dump in liggghts?

Thanks a lot for your kind help!

Best,
Tong

ckloss's picture

ckloss | Wed, 04/06/2011 - 10:06

Hi Tong,

no these are old comments. If you use a recent version, you can access the per-particle drag force with f_dragforce[0], f_dragforce[1], f_dragforce[2]

tshan | Wed, 04/06/2011 - 10:43

Hi Christoph,

Thanks for you reply! Can I dump like this?

dump dmp all custom 500 post/dump.liggghts_init id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius f_dragforce[0] f_dragforce[1] f_dragforce[2]

But I got ERROR: Could not find dump custom fix ID.

And how about other variables, like cell id?

Thanks again!

Best,
Tong

ckloss's picture

ckloss | Wed, 04/06/2011 - 10:54

sorry, that was a typo, I meant f_dragforce[1] f_dragforce[2] f_dragforce[3]
The dump command must come after the fix couple/cfd/force
What version of LIGGGHTS are you using?

>>And how about other variables, like cell id?
this is basically no problem, but you would have to modify the code to have these properties transferred.

Christoph

tshan | Wed, 04/06/2011 - 14:29

Hi Christoph,

Thanks for your explanation.

I am using both 1.1.0 and the latest version... Just ran it in them, both no problem.

Best,
Tong