Please include project files - Main menu/Submit bug report - attach zip
Hello,
I have tried to set up a MFiX file for the case presented in the attached paper. It involves a tube and a cup. I set up everything but getting some error messages as attached. I am attachig the zipped error file. Kindly have a look and tell me where I am getting it wrong. May be the outflow boundary condition at the top is a problem. I am also attaching the two stl files. One for the tube and the other for the hemispherical cup below the swirling chamber.
I look forward to hearing from you.
Thanks and Regards,
Debashis
tube-cup-separate-dpi-dem_2025-10-30T124251.080633.zip (2.5 MB)
Alfano et al model2a-body.STL (15.6 KB)
Alfano et al model2a-hemisphere.STL (155.9 KB)
alfano-et-al-2021-full-scale-dem-simulation-of-coupled-fluid-and-dry-coated-particle-flow-in-swirl-based-dry-powder.pdf (6.9 MB)
file here.
tube-cup-separate-dpi-dem_2025-10-30T161558.676542.zip (2.5 MB)
I checked everything and ran and it gave the same error. It will be really helpful if I can some help and suggestion on this so that it runs.
Thanks and Best Regards,
Debashis
I haven’t tried to run your model, but the snapshot indicates that the BC#2 zmin and zmax are flipped. You should also make sure the stl extends past the MFiX box where you have inlets and outlets, and check the stl normal vectors. Please invest some of you time to learn the basics of the mesh setup, this will help you fix common mistakes. Please see the doc below:
Dr. Dietiker,
Thank you. I went over this same tutorial before building my case. I will still check the BC#2,
I will again review it. In many cases (tutorials) I see numerical values used for the boundary geometries and in many cases, I see use of “xmin/xmax/ymin/ymax/zmin/zmax” instead of numeric values.
If you kindly have a first look at the model and let me know if there is any other error, it will be helpful.
I will keep you posted.
Thanks, and Best Regards,
Sincerely,
Debashis
I will review after you confirm you have checked the STL normal orientation, and made sure the stl extends past the box at inlets and outlets.
Dr. Dietiker,
Thank you. I will let you know when I am done. Just confirming that in order for the stl file to extend past the box at inlet and outlets I need change the dimension of the box. Let me know if I am correct.
Best Regards,
Debashis
You can either change the dimension of the box or change the dimension of the stl geometry.
tube-cup-separate-dpi-dem_2025-10-31T143150.682118.zip (4.4 MB)
Dr. Dietiker,
As per your suggestion and advice, I checked the STL normal orientation and made sure the stl extends past the box at inlets and outlets. The normals are pointing towards the fluid region. I have set up the BC but have issue with specifying the particles in the cup as IC. Also, it is having issues with generating the mesh and subsequent running. Please ignore the zipped files I uploaded yesterday. This is the most recent version and kindly have a look and let me know how I can get rid of the error and get the solution running. Also, I need to specify the particles within the hemispherical part as initial condition.
Thanks for all your help, guidance and advice and I look forward to hearing from you regarding this case and running it.
Thanks and Best Regards,
Sincerely,
Debashis
You have not extended the inlets past the box, they are sitting inside the domain:
You can decrease xmax and increase xmin, say xmin=-0.008 and xmax=0.008.
Your STL files are still not good. The hemisphere is closed where it should meet the vessel, and the vessel is also closed there. You need to combine them so there is no internal wall.
Let’s first make sure you can mesh and run a single phase simulation. Then you can add the particles. There is no option to seed the particles in a hemispheric region, so you will have initialize them in a rectangular region and let them settle, but work first on your mesh.
You are not going to make any progress until you understand you cannot have a zero thickness wall between the cup and the vessel. The latest setup is still using the same stl files, i.e. the cup and vessel have not been combined and the internal wall is still there. You also added particles while you should be focusing on a single phase flow.
I am going to let others assist you as I am unable to get my message across. Good luck!
