Warning: Dangerous build in triangle neighbor list

Submitted by knoe_ph on Wed, 05/09/2012 - 18:08

Hallo everybody,

while trying to build a quite simple simulation (basically some granular particles inserted in a cylindrical box) i get multiple warning messages: "Dangerous build in triangle neighbor list" when executing my simulation.

These warnings don't appear right at the beginning of simulation, but at a quite early stage.

Visualised in ParaView, it looks like this:

The particles start settling on the ground of the cylinder. All of a sudden, the particles "explode" and most of the particles dissapear out of my simulation environment (at the beginn of simulation i got 1600 particles, after the series of warnings there only remain 60 particles).

Since I don't really have a clue what this warning message means or how it can be fixed, I'm looking for help here.

Thanks in advance and kind regards,
Philipp

Philippe's picture

Philippe | Thu, 05/10/2012 - 14:07

Hello Philipp,

how long is you timestep? The problem sounds like it is too long. If this is the case, the particles are allowed to travel too far in one timestep, thus overlap more with the wall and experience a way too high repulsive force, resulting in the "explosions" you described. You can check this by a command like

fix ts_check all check/timestep/gran 1000 0.1 0.1

(see documentation for further information on the fix)

greetz
Philippe

xinze_l | Wed, 06/13/2012 - 11:11

I have experienced the same problem, but method I used is increasing the timestep, I don't known why?
who can explain?
thank you!

xz

ckloss's picture

ckloss | Sat, 06/16/2012 - 11:12

Another probably reason is that the particles you insert overlap with a wall, which should be avoided

Cheers, Christoph