I am a beginner using Mfix software. I am trying to simulate a steady, 2D Poiseuille flow, lid-driven square cavity problems using Mfix GUI, I followed the same procedures as mentioned in the manual, but I could not get the desired output. Can you advise me with this?
Hi Samah.
When looking for help, please provide as much detail as possible. Use the Submit bug report feature to create a ZIP file containing all relevant files for your simulation. And please explain what results you expected, and how the results you obtained differ from your expectation.
Thanks,
– Charles
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Thank you so much for your response!
Attached is the ZIP file for lid-driven cases reported in the verification and validation manual. I am trying to obtain the following figures, however, when I open it using Paraview software, There is no data to display.
Another case for 2D Poiseuille flow case, I was able to obtain the following results in Paraview software for U_g and P_g. However, when I drew them I got flat horizontal line not similar to the one in the manual ( I attached the plot from the manual)
gggggg_2022-02-08T103346.462851.zip (10.1 MB)
Lid driven cavity:
Your residual tolerance is wrong: tol_resid = 5.0000e+03 I guess you meant tol_resid = 5.0000e-03.
You should also remove bc_hw_g(4) = 0.0 form the file (i.e. leave it undefined).
You will also need to extract the velocity profiles as a typical post-processing step.
You have a working file at:
https://mfix.netl.doe.gov/doc/vvuq-manual/main/html/fluid/fld-03.html#setup
Poiseuille flow:
What you see in Paraview is the entire domain, colored by x-component of the velocity. You need to actually extract the velocity profile (in the y-direction) and the pressure along the x-direction.
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Thank you so much!
Can you advise me on how to do a typical post-processing step? I checked the MFIX download contents for the test file, and there is a Fortran file to extract the velocity profiles. However, I do not know how to use it or extract them directly from the Para View (I used the plot data filter but I didn’t get it as reported in the manual).
I am sorry for asking basic questions, but I am still in the learning stage and I am a little bit lost.
In Paraview, you can use the “Plot over line” filter to extract the data. Then you can inspect it using the spreadsheet view in a new layout. You can also save the data in csv format in File>Save data.
We also have a tool called postmfix that can be used to extract data from the SPx files:
https://mfix.netl.doe.gov/doc/mfix/21.4/html/visualization/postprocessing.html#building-postmfix
https://mfix.netl.doe.gov/doc/mfix/21.4/html/visualization/postprocessing.html#running-postmfix
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Thank you so much!
when I plot the velocity for 2D Poiseuille flow, I get the plot as attached. how can I get it as same as the one in the manual (smooth curve and direction)
fld01_2022-02-12T165739.658973.zip (94.0 KB)
I am really sorry for asking a lot. can you help me how can I get these figures using Paraview. I was trying, but I am sure I am doing sth wrong while I am using paraview
fld03_2022-02-12T170711.294947.zip (154.5 KB)
Samah - Asking questions is fine, but I’m not that familiar with Paraview.
There is a Paraview help forum at this link: https://discourse.paraview.org/
– Charles
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You need to decrease the resolution of the line so you have as many points as there are cells along the profile.
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