Hi,
While setting up a case for a CFDEM simulation, we encountered a problem with the perceived packing density.
We first inserted the particles mid-air and let them settle. The bed height after settling was much higher than in reality, which is why we tried a higher gravity as well as shrinking the particles and cycling between growing and relaxing, to no avail.
Has anyone had a similar issue before? We would appreciate any response.
ckloss | Mon, 09/07/2015 - 13:53
Hi,
Hi,
I am not sure if I completely got what exactly the issue is.
Normally, the initial packing fraction is calibrated as part of parameter calibration
Best wishes
Christoph
Swantje | Tue, 09/08/2015 - 08:12
Thank you for your attention.
Thank you for your attention.
We have a complex geometry (prismatic) that we are intending to fill, which is why we insert a fixed number of particles mid-air. The packing density after settling is much lower than experimentally determined.
Best wishes
Daniel Queteschiner | Tue, 09/08/2015 - 09:16
Hi Swantje
If your simulation setup mimics the filling procedure of your experiment you should get similar results for the packing density. Factors that might influence the volume fraction are the asphericity and polydispersity of your particles. Also the coefficients of (rolling) friction of the wall and particle material might influence the settling process and in further consequence the resulting packing to some extent. Just my two cents ...
JoshuaP | Tue, 09/08/2015 - 09:30
Maybe try to insert them with
Maybe try to insert them with mass_in_region. Calculate your necessary mass and then insert the particles in a bit larger region and let them settle with rolling friction and friction.
regards
Joshua