Dear users,
currently i am working on a rotating drum mixing project. I found something is strange to me (please refer to the attached fig.). Sometimes the particles are jumping and flying. i had same issue in other mixer (the reason was due to the mesh). i have tried again playing with finer mesh. still have the same probelm. What do you think might be the reseaon? here is the parameter i am using:
#mat1->alumina; mat2-> drum chamber
fix m1 all property/global youngsModulus peratomtype 5.e6 5.e6
fix m2 all property/global poissonsRatio peratomtype 0.25 0.25
fix m3 all property/global coefficientRestitution peratomtypepair 2 0.55 0.6 0.6 0.6
fix m4 all property/global coefficientFriction peratomtypepair 2 0.8 0.55 0.55 0.55
fix m5 all property/global coefficientRollingFriction peratomtypepair 2 0.05 0.05 0.05 0.05
fix m6 all property/global cohesionEnergyDensity peratomtypepair 2 10 50 50 50
pair_style gran model hertz tangential history cohesion sjkr2 rolling_friction cdt
pair_coeff * *
### Detailed settings
# Integration
fix integrator all nve/sphere
# Gravity
fix grav all gravity 9.81 vector 0.0 -1.0 0.0
# Timestep
timestep 0.000005
Best regards,
Zyan
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Nafets | Tue, 02/03/2015 - 15:57
Check your Timestep
check your Timestep with
fix check/timestep/gran command
Rayleigh time should be smaller 20%
ZYan | Tue, 02/03/2015 - 16:08
Yes. i did. i think the time
Yes. i did. i think the time step is fine, as no warning when using fix ts all check/timestep/gran 100 0.1 0.1
cheers, Zyan
richti83 | Tue, 02/03/2015 - 17:10
particle diameter
What are the settings for radius and neighbour bin size ?
For small particles the Young Modulus seems very low.
Neighbourbinsize should be D_max of your particles.
coefficientRestitution is very high, normaly I use 80% damping, cor=1-D=0.2 which is even higher than normal ..
ckloss | Mon, 02/09/2015 - 12:59
You also may want to increase
You also may want to increase the Youngs Modulus, the value you are using is too low for a real simulation
Christoph
ZYan | Mon, 02/09/2015 - 17:40
Hi Christoph,
Hi Christoph,
Thanks for your commments. This was a test to see how fast our simulation can be. I will use reasonable values for real simulations.
i will get some feedback once i have finished my simulations.
Cheers,
Zyan