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-   -   Theory of wing sections experimental data. (https://www.cfd-online.com/Forums/fluent/157602-theory-wing-sections-experimental-data.html)

koalabryant August 3, 2015 07:09

Theory of wing sections experimental data.
 
Hi

This is my first time posting hereĦĦ I hope it would be interesting.

I am working on a 2d airfoil with fluent testing several airfoils (4412, 63-215, 64-108, 4418 ...) and I have problems when it comes to validate the experimental data for these airfoils with my fluent cases.

Before use any of these airfoils I tried to validate my grid with Naca0012 experimental data based on: http://turbmodels.larc.nasa.gov/naca0012_val.html

With this data, my fluent case behaves perfectly and I get very good results, but when I try to change to the theory of wings sections data and I try to validate one of the the airfoils listed above it is impossible to match the results both cd and cl coefficients.

Any suggestions?


PD: My setup is:
pressure based steady
Re 6e6
y+ ~ 1
k-epsilon enhanced wall treatment
SimpleC
2nd order upwind
C-Mesh 20 times chord length long

Aeronautics El. K. August 3, 2015 08:35

Did you try SA or SST k-omega for the turbulence modeling?
I think I had a similar problem with those cd values which were closer to the skin friction drag coefficient but I can't be sure because it's quite long time since then.

Quote:

Originally Posted by koalabryant (Post 558153)
Hi

This is my first time posting hereĦĦ I hope it would be interesting.

I am working on a 2d airfoil with fluent testing several airfoils (4412, 63-215, 64-108, 4418 ...) and I have problems when it comes to validate the experimental data for these airfoils with my fluent cases.

Before use any of these airfoils I tried to validate my grid with Naca0012 experimental data based on: http://turbmodels.larc.nasa.gov/naca0012_val.html

With this data, my fluent case behaves perfectly and I get very good results, but when I try to change to the theory of wings sections data and I try to validate one of the the airfoils listed above it is impossible to match the results both cd and cl coefficients.

Any suggestions?


PD: My setup is:
pressure based steady
Re 6e6
y+ ~ 1
k-epsilon enhanced wall treatment
SimpleC
2nd order upwind
C-Mesh 20 times chord length long


koalabryant August 3, 2015 09:07

Yes. I have tried other methods with different y+ values and I don't get the same values of the Naca 824 report.

But what I'm trying to figure is the validity of this reports in order to compare fluent cases or any other CFD code.

For example if you search for additional Naca 0012 experimental data there are other reports like Naca report 460.
If you check the lift curve of Naca 0012 is this report, even though is at Re=3e6, the linear zone has nothing to do with the previous data I post before of Naca 0012 validation. http://turbmodels.larc.nasa.gov/naca0012_val.html

So I think there is something I'm missing about tunnel experimental data and it's driving me crazy.

thanks


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