No Particles Inserted

Submitted by gabrielmsa on Wed, 10/18/2017 - 14:33

Hello!

I'm new to CFDEM and I'm trying to run a simulation of a turbulent flow on a pipe with particles inside. However, when I ran the LIGGGHTS script it didn't insert the particles at all. Does anyone have any idea of why is this happening?

Thanks in advance!

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Plain text icon in.liggghts_init.txt2.37 KB
Plain text icon log.liggghts.txt4.69 KB
Plain text icon log2.liggghts.txt1022.92 KB

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alice's picture

alice | Wed, 10/18/2017 - 14:50

Hi Gabrielmsa,
first of all I'd recommend to use units box at the end of the definition of reg2 as well (see def. reg, here it's correct). If this doesn't do the trick, please also post the log file you get, this will tell us a bit more.
Cheers,
Alice

gabrielmsa | Wed, 10/18/2017 - 16:24

Hi Alice,

thanks for the quick response! I made the changes you suggested but still the particles are not being inserted. I attached the log file to the first post.

Thanks in advance!

Daniel Queteschiner | Thu, 10/19/2017 - 10:57

The line
WARNING: Particle insertion: Less insertions than requested (/build/liggghts-QCz4in/liggghts-3.3.1+repack1/src/fix_insert.cpp:734)
indicates that the insertion region is too small to hold all particles. Note that the insert/pack command does not produce a dense packing. You will typically end up with a packing density less than 0.35. You may try to increase the maxattempt parameter or define a larger region.

gabrielmsa | Thu, 10/19/2017 - 13:50

Hi Daniel,
thanks for the response! I changed the region of insertion so that now it is the same region as the domain, which has double the volume. I also changed the radius of the particles to 0.002 (1% of the previous value), the dump to 100 and increased the number of particles being inserted to 100. Then I ran the LIGGGHTS script and the warning message no longer appeared. However, the particles are still not being inserted. I attached a second log file (log2.liggghts) to provide more information on this.

gabrielmsa | Thu, 10/19/2017 - 15:22

I just found out what was going wrong. I had a problem with the units in the CFD part and the DEM part. After correcting the units, the particles appeared. Thanks for the help!