yade-dev team mailing list archive

[Vincent Richefeu <richefeu@xxxxxxxxx>]

Le 23 févr. 2011 à 17:43, Bruno Chareyre a écrit :

> p.s. Vincent, you defined viscosity in order to keep critical time-step below a given value IIRC. What was the reasoning behind?

No. I (and other people like Sergei) defined the viscosity so that it is lower than the critical viscosity. If the viscosity is bigger than this critical viscosity the second order differential equation leads to an overdamped solution (which means exponential decays of the normal distance and thus the bodies never touch one another!). For practical reasons, one introduces a parameter which is a rate of the critical viscosity.

Sergei went further in the law he implemented in yade... 

For some applications, the viscous damping leads to unphysical situations... I wil not dwell on the topic.

Vincent