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simpleFoam kOmegaSSt boundary conditions

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Old   April 1, 2022, 06:14
Default simpleFoam kOmegaSSt boundary conditions
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Sean
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Hi everyone,

I’m a long time visitor and lurker on the forum. Today I’m making my first post! Thank you in advance

I’m struggling to get a simpleFoam kOmegaSST turbulence model to run on OF7.

The cases existed in the department, though I had to make two changes to get simpleFoam to run:
  • in constant/fvOptions > momentumsource I changed “fieldNames” to “fields” (this tells that the case used to run on a different version of OF?)
  • in 0/nut the walls had “calculated” which gave errors so I changed it to “nutLowReWallFunction”.
The initial conditions are read in properly, but when running simpleFoam the solution is not right. Please see the attached image of the velocity field on the 0th, 100th and 500th iteration. Judging from the field I suspect something is wrong with BC on either the inlet or walls.

I have a working case of kOmegaSST which has largely the same BC, although in that case the inlet and outlet are cyclic so I cannot compare the inlet and outlet. I have tried many different values, settings and wall functions but the results remains wrong. Can anybody help me spot the issue?

Due to the interpolated values the files are too large to attach, please see a summary of the 0 directory below. If anyone requires more information or files please let me know!

U:
internalField --- nonuniform List (interpolated LES data)
inlet ------------ fixedValue nonuniform List (… fully developed channel flow)
topWall --------- fixedValue uniform(0 0 0)
bottomWall----- fixedValue uniform(0 0 0)
outlet ---------- zeroGradient

p:
internalField --- nonuniform List (interpolated LES data)
inlet ------------ zeroGradient
topWall --------- zeroGradient
bottomWall----- zeroGradient
outlet ---------- fixedValue uniform(0)

nut:
internalField -- nonuniform List (interpolated LES data)
inlet ------------ calculated nonuniform List (… fully developed channel flow?)
topWall -------- nutLowReWallFunction uniform 3e-18
bottomWall---- nutLowReWallFunction uniform 3e-18
outlet --------- calculated nonuniform List (… fully developed channel flow?)

both top and bottom walls had “calculated” instead of “nutLowReWallFunction”, but simplefoam couldn’t run with calculated. I think nutLowReWallFunction is appropriate.

omega:
internalField ---- uniform 0.11
inlet ------------ fixedValue nonuniform List (… fully developed channel flow?)
topWall --------- omegaWallFunction uniform 1000
bottomWall----- omegaWallFunction uniform 1000
outlet ---------- zeroGradient


k:
internalField ---- nonuniform List (interpolated LES data)
inlet ------------- fixedValue nonuniform List (interpolated LES data)
topWall --------- fixedValue uniform 1e-15
bottomWall----- all fixedValue uniform 1e-15
outlet ---------- zeroGradient
Attached Images
File Type: jpg iteration_progress.jpg (60.7 KB, 18 views)

Last edited by DataDriven; April 1, 2022 at 11:32.
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Tags
boundary condition, initial conditions, komegasst, simplefoam, simplefoam initialisation


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