ESyS-Particle

Simulation stops at mesh contact

Asked by Martin Nie

Hi,
I used the Hopperflow.py skript and changed the mesh. The mesh represents a bowl. I decreased the particle radius, bBox and bounding box. I adapted cubicradius, gridSpacing and verletDist to the decreased particle radius. If I start the simulation, it stops at 100000 steps, although I expected the simulation to stop at 250000 steps. If I open the simulation in paraview, i can see, that the simulation stops near to the bottom of the bowl. How can i solve this problem ? Does somebody experienced an equal case? I'm new to esys, so hopefully you can help me.

Martin

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Oguz Cebeci (oce1907) said : 		#1

I tested the same thing, but my problem is, that the simulation is getting very slow. It could be the same reason as yours. Any solutions?

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Oguz Cebeci (oce1907) said : 		#2

I should also add. Particles are flying away when they reach the Mesh. I tried it with a very small time step: t =1.0e-07

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Feng Chen (fchen3-gmail) said : 		#3

Hi, Martin and Oguz:

Not very sure however your problem might relate to my previous question here:

https://answers.launchpad.net/esys-particle/+question/146375

Basically the wall has direction.

When your simulation becomes slow there might be already some numerical instability there and results are unusable.

Feng

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Dion Weatherley (d-weatherley) said : 		#4

Hi all,

I concur with Feng that the problem is probably with the ordering of nodes defining triangles in the mesh. The Tutorial explains the correct ordering of nodes to avoid numerical instability and particles "tunnelling" through mesh walls.

The slow-down is most probably because particles have obtained a very high velocity, requiring very frequent updates of the neighbour table. This will drastically slow down simulations.

Cheers,

Dion

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