yade-dev team mailing list archive

[Luc Sibille <luc.sibille@xxxxxxxxxxxxxx>]

Hi Boon,

It may be due to the fact that the DEM is a numerical method: at each 
time step particle velocities and positions are deduced from a numerical 
integration of Newton's law. This numerical integration is based on 
finite differences which accuracy depends on the size of the time step.
To check if it can be the reason why the energy is not conserved in your 
simulation, just run again the simulation for smaller time steps (dt/10, 
dt/100, etc...), then error in energy conservation should decrease with 
time step.

Best regards,
Luc

Le 27/03/2012 17:54, ChiaWeng Boon a écrit :
> Hello everyone,
>
> If you run the attached script long enough, you will see kinetic
> energy increasing.  There is no damping so it should be constant.   Do
> you get what I get too? Do you think somewhere went wrong?
>
>
> Regards,
>
> Boon
>
>
>
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--
Luc Sibille

Université de Nantes - Laboratoire GeM UMR CNRS

IUT de Saint Nazaire
58, rue Michel-Ange - BP 420
44606 Saint-Nazaire Cedex, France

Tel: +33 (0)2 40 17 81 78