Hi, I am using PIC method to do a simulation and it begins well but after running for about hundreds of steps, it will show the error as ‘DT < DT_MIN. Recovery not possible!’ and the simulation will stop. ctfb_1_2023-03-19T164442.382008.zip (1003.6 KB) i could not really locate where causes this…

This is a common mistake. Please see items 1-4 from: [image] Running stl file error How to A few things: You should only include the interior wall of the geometry in the STL file. Here you have both sides. You should orient the normal vectors so they point towards the f…

Hello sir, thanks a lot for your reply. I wonder for all the suggestions you said, can they be set within MFiX? I went through the ‘geometry’ part but couldn’t find any place to set up the things you mentioned. I am a very new user of this software, so sorry if I am asking some very fundamental qu…

You will have to clean the STL file outside the GUI (i.e. with the software you used to generate the STL file). Other steps can be done in the GUI. I would recommend going through this step by step tutorial: https://mfix.netl.doe.gov/doc/mfix/22.4/html/tutorials/tutorial_cyclone_sms.html It is lik…

Hello sir, Sorry for disturbing you again. Because i am not sure how to only include the interior wall, I tried to set the wall thickness to zero, i thought this is supposed to work but it didn’t, i still have normal on both sides of the wall :sob:, May I ask is this my problem or this way just doe…

This needs to be done in the software (CAD) you used to create the STL file. Right now, you created the geometry by creating an object that represents the walls only. You want to create an object that represents the fluid region. In other words you want to remove all the faces where the vector point…

thank you sir, your advice was really useful~

DT < DT_MIN. Recovery not possible!

MFiX

jeff.dietiker March 20, 2023, 7:30pm 2

This is a common mistake. Please see items 1-4 from: