Hello,
I want to simulate particle flow i.e. Angle of Repose.
I want to used particle size between 50 and 150 µm but unfortunately it is not working. The particles are spreading outside the container.
Particle greater than 400 µm is only working.
I am using SI units in the code. i.e. 0.0004 (400 µm)
Could you please help me to solve the problem?
Thanks in advance.
Best regards,
Bilal
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MiRa | Tue, 01/09/2018 - 16:36
Time step?
Hi Bilal,
your problem description is somewhat short. So, I am guessing what could be the cause:
1. Did you adjust your time step accordingly? If your time step remains the same for the smaller size, your particles may suffer from excessive contact overlaps. This leads to effects, which look as if the particles were subject to a blast, i.e., they "shoot away".
2. You could consider changing the unit system from "SI" to "micro" or "nano"
Kind regards,
MiRa
bilalelkassem | Wed, 01/10/2018 - 11:13
Neighbor list overflow & changing to cgs units
Thank you Mira.
I changed to cgs units and for some time it works well before I get such an error: Neighbor list overflow, boost neigh_modify one liggghts....
I have a problem also in changing the Youngs Modulus value from SI units to cgs units. In Si it os 2.5e7, what would it be in cgs units? I wrote 250 but an error came saying it should be minimum equal to 5e5.
Any suggestions?
Philippe | Thu, 01/11/2018 - 14:41
The SI unit for pressure is
The SI unit for pressure is barye (Ba) and 1 Ba = 0.1 Pa - so you need 2.5e8 to match your Youngs Modulus.
Daniel Queteschiner | Thu, 01/11/2018 - 16:32
Ouch!
I know it's just a careless mistake, but shame on you Philippe ;-)
The SI unit for pressure is the pascal (Pa), the CGS unit of pressure is the barye (Ba) (and yes, 1 Ba = 0.1 Pa).
Young's modulus is the ratio of stress (which has units of pressure) to strain (which is dimensionless), and so Young's modulus has units of pressure.