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[Bug 806944] Re: different behavoir of Hertz model while comparing PFC and YADE

 

Thank you for the hint, Anton.
I divided kn with the mass of the balls and the result is the same as in pfc.

results yade:
step                   normal force
1.000000e+00  -5.000000e-06 
2.000000e+00  -9.902892e-06
3.000000e+00  -1.461345e-05
4.000000e+00  -1.904020e-05 
5.000000e+00  -2.309715e-05 
6.000000e+00  -2.670551e-05 
7.000000e+00  -2.979521e-05 
8.000000e+00  -3.230624e-05 
9.000000e+00  -3.418982e-05

results pfc:
step                   normal force
 2.0000e+000  5.0000e-006
 3.0000e+000  9.9029e-006
 4.0000e+000  1.4613e-005
 5.0000e+000  1.9040e-005
 6.0000e+000  2.3097e-005

 7.0000e+000  2.6706e-005
 8.0000e+000  2.9795e-005
 9.0000e+000  3.2306e-005
 1.0000e+001  3.4190e-005

Conclusion: linear model works the same way in both programs!

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https://bugs.launchpad.net/bugs/806944

Title:
  different behavoir of Hertz model while comparing PFC and YADE

Status in Yet Another Dynamic Engine:
  Confirmed

Bug description:
  Hello,

  During verifiing my model I compared output from PFC 4.0 with the
  output from YADE (bzr2877 on Debian Squeeze 64bit). There I found a
  different behavior between these two programs. I dont know if this is
  a bug or not, but I hope someone can explain the different behavior.

  The model itself is very simple. There are two spheres, an upper one and a lower one. The lower one is fixed and the upper one is falling down to the lower one, collides and jumps back. The value of interest is the flyback height of the upper particle.
  In PFC I measure higher values of flyback height, then in YADE (see log-files in the attachment).

  Can someone tell me why there is a difference in the flyback height?
  (input parameters are the same for both programs ... see caller_two-spheres-jumping.dat for PFC and two-spheres.py for YADE)

  Regards,

  Christian Jakob

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