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How to write a time-varying pressure gradient inlet? |
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#1 |
New Member
Guo Zongchao
Join Date: Nov 2021
Posts: 8
Rep Power: 4 ![]() |
Hello, everyone.
I meet a trouble while setting pressure gradient. My inlet pressure gradient is time-varying, and there is a formula looks like dp/dy=acos(ωt). ZeroGradient and fixedGradient are all useless for me. How could I write this inlet condition? I would appreciate it if someone could give me some ideas. |
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#2 |
Member
Lukas
Join Date: Sep 2021
Posts: 36
Rep Power: 4 ![]() |
Hello Crane,
i don't know if u already found a solution for your problem, if not : Go to the userguide for foam there u will find this chapter : https://cfd.direct/openfoam/user-guide/v9-boundaries/ 5.2.3.4 Time-varying boundary conditions (Openfoam 8/9) I think u find your answer there |
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#3 | |
New Member
Guo Zongchao
Join Date: Nov 2021
Posts: 8
Rep Power: 4 ![]() |
Quote:
Thank you very much for your kind reply. Actually I know these time-varying boundary conditions, but I think they can only used for pressure condition, instead of pressure gradient condition. For pressure gradient, I only find conditions like zeroGradient and fixedGradient, but they all can't be used for changing gradient. |
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#4 |
Member
Lukas
Join Date: Sep 2021
Posts: 36
Rep Power: 4 ![]() |
The Function1 should be implemented in FixedGradient also:
find $FOAM_SRC/finiteVolume/fields/fvPatchFields -type f -name "*.H" | xargs grep -l Function1 OpenFOAM-8/src/finiteVolume/fields/fvPatchFields/derived/uniformFixedGradient/uniformFixedGradientFvPatchField.H at least does the search say so (I never used variable gradients) |
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#5 | ||
Senior Member
Julio Pieri
Join Date: Sep 2017
Posts: 105
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Quote:
Code:
wall { type fixedGradient; value uniform 416.67; } From the UserGuide link provided: Quote:
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#6 |
New Member
Guo Zongchao
Join Date: Nov 2021
Posts: 8
Rep Power: 4 ![]() |
Thanks for your help. I got some inspiration from both of your replies, and write like this
Code:
INLET { type uniformFixedGradient; uniformGradient cosine; frequency 0.2; amplitude 2*pi/5.00*1.00; scale 1; // Scale factor for current level 0; // Offset } Anyway, thanks for giving me ideas to solve the problem. |
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#7 |
Senior Member
Sakun
Join Date: Nov 2019
Location: United Kingdom
Posts: 107
Rep Power: 6 ![]() |
Hello everyone,
Sorry to jump into this thread, I am running compressor blade simulation and i need to give total pressure gradually for my simulation. can get some suggestions from your expertise ? Thanks in advance ![]() |
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Tags |
pressure gradient, time varying |
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