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DEM - Post Processing - Packing Fraction of particles |
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August 26, 2014, 18:03 |
DEM - Post Processing - Packing Fraction of particles
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#1 |
New Member
Yesaswi
Join Date: Jan 2014
Posts: 26
Rep Power: 12 |
Hi,
Is there anyway where we can find the packing fraction of particles. I am injecting particles into flow domain and they settle at the bottom of the domain. Is there anyway, where I can find the packing fraction of the deposited particles? Also is there a way, where I can get a cross-sectional image of the settle particles? In that way I can see the particle and void space distribution Thanks a lot. Yesaswi |
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August 27, 2014, 08:21 |
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#2 |
Senior Member
Ping
Join Date: Mar 2009
Posts: 556
Rep Power: 20 |
there is a field function called void fraction in the continuous fluid so use this but you might need to have 2 way coupling enabled for this to have values
to see particles internally use normal methods like a threshold or clipping planes but be careful on judging packing this way unless you are displaying particles at their real size since they can be scaled up and down like all lagrangian particles |
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August 27, 2014, 12:49 |
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#3 |
New Member
Yesaswi
Join Date: Jan 2014
Posts: 26
Rep Power: 12 |
- I tried to create a report with void fraction as the scalar function. It gives 1 which is definitely wrong. I used both phases separately and together in the parts properties but there is no change. The two way coupling was also 'on' but there was no change. Could to help me in evaluating the value? Also how should the report be? I mean is it volume averaged, sum or any other thing?
- For seeing the particles, I am using clip planes only. But that does not cut the domain and show us a section. So that is the reason I am looking for other way, where I can have a neat cut through the domain such that the particles are also sectioned across the plane. - While using threshold, what function should I use? Is there a way where I can cut through a plane. - Regarding the size of the particles, I am using a scalar field (particle size) for the point size. |
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August 28, 2014, 05:45 |
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#4 |
Senior Member
Ping
Join Date: Mar 2009
Posts: 556
Rep Power: 20 |
i have tested this in the completed dem tutorial for the conveyor belt as downloaded from steve so it is done correctly
first turn on 2 way coupling then create a new scalar scene and add a section plane to this through the vertical center of the domain and display the field function void fraction then clear the solution and run again and you will see clearing where the particles are occupying the fluid space even on this very coarse mesh if you want to report on this voif fraction field then use for example a volume integral report clipping planes dont seem to work too well on that case so maybe this is problem but thresholds do create a new threshold with the grain as the input part and use position z say between .01 and .2 to limit the particle range, and this creates a subset of the particles in that range of z then add this threshold to a displayer to show them eg the existing scalar scene 1 scalar displayer |
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August 28, 2014, 13:04 |
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#5 |
New Member
Yesaswi
Join Date: Jan 2014
Posts: 26
Rep Power: 12 |
Thanks again for the reply.
The void fraction function worked and I am getting the required reports!! I tried to play with the thresholds but it is the same like clipping planes. If the particle centroid is outside the threshold range, then the entire particle is chucked out even if a small portion of the particle is still withing the threshold. I guess I just need to use this option clubbed with void fraction values to extract the information. Thank you for the help. |
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August 29, 2014, 05:18 |
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#6 |
Senior Member
Ping
Join Date: Mar 2009
Posts: 556
Rep Power: 20 |
yes that is the way clipping and thresholds work with particles it appears based on the centroid location probably so you cant display a portion of a particle
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Tags |
dem, lagrangian particles, packing fraction, particle, star ccm+ |
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