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-   -   Postprocessing UPrime2Mean(-normed /Magnitude) for a DFSEM-Mod (https://www.cfd-online.com/Forums/openfoam-post-processing/224729-postprocessing-uprime2mean-normed-magnitude-dfsem-mod.html)

stud-many March 2, 2020 11:35

Postprocessing UPrime2Mean(-normed /Magnitude) for a DFSEM-Mod
 
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Question regarding OpenFOAM and Large Eddy Simulations (using rhoPimpleFoam and a turbulent Inlet-Patch). Hey. I am modeling a turbulent flow with a turbulent inlet-patch. I programmed a Mapping for UMean and R Field-Values for the Inlet-Patch and i used Data from a streamwise periodical Simulation. I somehow can't use a anisotropic R-Field for my turbulent Inlet-Patch. Therefore i am trying to approximate the Stress-Profile isotropical. Right now I am using "UPrime2Mean-normed" aka "Uprime2Mean-Magnitude" to construct such a profile and i am scaling the isotropic R-Field so that I achieve similiar fluctations to the periodical Simulation. But what I did not found out until now is: WHAT is UPrime2Mean-Magnitude and what is the correct way to approximate an isotropic Reynoldssstressfield from it?

THANKS. I am new to all this turbulence-stuff. I love it, but i don't understand much of the mathematical Modelling as I am still quite unexperienced.

The picture shows the instantanious y-Velocity of the tiurbulent Inlet-Patch. I only show it to make PPL more curious about my work

Sereff April 9, 2020 11:51

Hi Malte,

I probably don't know better than you do and this could be a late answer. To my understanding UPrim2Mean is <UiUj> - <Ui><Uj>, which is sampled from the 'resolved' flow field of your simulation. And it differs from R, which is Ui'Uj' and it is modeled/calculated by the turbulence model you used in your simulation.


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