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[chiara modenese <c.modenese@xxxxxxxxx>]

Hi all,

I am playing a little bit with the code to understand how thinks work in
terms of energy. I started with a very simple example of two balls in normal
contact.
I am only applying an initial velocity to one particle, hence the total
energy of the system is only given by (kinetic + potential elastic).
Look at the two attached figures. The first one (dt_crit) is the result
obtained using the critical time step computed by Pwave in Yade. The second
one (dt_Econst) is obtained decreasing the time step to get the total energy
constant.

Now I see that the time step influences the solution in terms of energy and
this is just a very little example (so it does not really quantify
anything). However, I have one consideration: does this mean that we are
mainly dealing with non conservative systems in our dem simulations? Is this
the right way to compute the total energy? I guess what happens in a system
with many bodies (I am gonna try)..

Thanks for your opinion,
Chiara

Attachment: dt_crit.png
Description: PNG image

Attachment: dt_Econst.png
Description: PNG image