LES WallFunctions in O.F. 2.2.0 (nutUSpaldingWallFunction)
Dear Foamers,
hi to all! new in the forum and, almost, in OpenFoam... so don`t complain too much :D I`m simulating a transiet injection of a high density fluid into a geometry filled with a low density fluid, solving with twoLiquidMixingFoam with this turbulenceModel:
My mesh is fine but, maybe, not enough for the physics of the case. So i want to check differences in the solution using and not wall functions. After this introduction let`s go to the questions:
Cheers Tommy p.s. i would ask about the new OF 2.2.0 settings for numerical schemes (http://www.openfoam.org/version2.2.0/numerics.php) to understand how does works a similar settings div(phi,h) bounded Gauss linearUpwind grad(h);... but maybe in a second time :o |
No suggestions? also the comment "stupid questions cannot expect great answer" would be useful!
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to 3) -> As far as I know the "value" in such cases is just used for the very first iteration (of the first time-step) as initialization. After that it uses the calculated value of your boundary condition. At least I don't worry about that.
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Hi Philipp, thanks for your reply!
So after the first iteration the uPlusWallFunctionData.gz is automatically read? I want to try to make you one more question: when this wall function is applied to 0/nuSgs how do you use to treat the boundary condition in 0/nuTilda? |
That's at least what I understood!
I am not 100% sure about the wall functions, because I don't catch on the whole code. But I think this is done by the "correctBoundaryConditions" command that comes after all the calculations in all the turbulence model files. Have a look at your LES model files! Maybe someone can confirm that? |
2 Attachment(s)
Hey there!
Playing around wallFunctions, in order to apply nutUSpaldingWallFunction is sufficient to set-up in 0/nuSgs: bottom { type nutUSpaldingWallFunction; value uniform 1e-4; } there is no need to use wallFunctionDict. I have some doubts about the nuSgs because the solved field seems to be strictly related to the initial value (as showed in the nuSgs chart). The effect of this wall function (about velocity) is showed in the attached file. blue line: wall function on left, LES solving (wall refined) on right red line: wall function on left and right About wallFunctionDict: seems to be necessary when you set in 0/nuSgs (or 0/nut 0/nuTilda etc etc) for the patch wall bottom { type nutTabulatedWallFunction; uPlusTable uPlusWallFunctionData; value uniform 1e-4; } (uPlusWallFunctionData have to be the same as setted-up in ./constant/wallFunctionDict) Thene you have to choice on ./constant/wallFunctionDict the kind of tabulated wallFunction (as shown in the following output from compiling trial): Valid tabulatedWallFunction types are: 2 ( SpaldingsLaw general ) Thene run on ./ wallFunctionTable and will be created a ./constant/uPlusWallFunctionData available for the computation. Just in this case the solver will read the generated table (i`m running a computation to confirm that) |
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