Postprocessing UPrime2Mean(-normed /Magnitude) for a DFSEM-Mod

stud-many · March 2, 2020, 11:35

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.

April 9, 2020, 11:51		#2
Sereff Member Sereff Join Date: Jan 2019 Posts: 48 Rep Power: 7	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. altinel likes this.