yade-users team mailing list archive

[chiara modenese <c.modenese@xxxxxxxxx>]

On 2 July 2010 23:27, Janek Kozicki <janek_listy@xxxxx> wrote:

> (sorry, working over vnc caused me to accidentally send before I
> finished writing this email - sending again)
>
> chiara modenese said:     (by the date of Fri, 2 Jul 2010 17:41:36 +0100)
>
> > Hi guys,
> >
> > I am experiencing again a bit of troubles with total energy conservation.
> > For a sphere-sphere impact test everything seems fine. Now I have tried
> > another simple example: few spheres with an input initial velocity in a
> box.
> > I attach the script, if you run it you will obtain the plot in the
> attached
> > figure. If there is no friction, then total energy is more or less
> constant
> > as shown in the first part of the plot (not exactly constant due to the
> way
> > we compute velocities, as already discussed in this thread
> > http://www.mail-archive.com/yade-users@xxxxxxxxxxxxxxxxxxx/msg01729.html
> ).
> > However, as long as I include some friction, both total and kinetic
> energy
> > decreases and no slip occurs since the function plasticDissipation() of
> > Law2_ScGeom_FrictPhys_Basic contact law returns 0. I have already checked
> on
> > paper and discussed with Bruno and the code which computes
> > plasticDissipation in ScGeom is formally correct.
>
> How about heat? Usually friction increases temperature of those
> bodies that are in friction. But in yade we don't have heat, so this
> turns into an energy loss.
>
In fact there is no heat effect at all in Yade, Janek could you elaborate
your thought? Energy must be conserved as long as the system is closed. I am
trying to see in a TT simulation what happens. Bruno, have you tried it?
Actually I am thinking to inlcude in the TTRecorder the various energy
terms, mechanical energy and so on.
Chiara


>
>
> --
> Janek Kozicki                               http://janek.kozicki.pl/  |
>
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