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Transition over airfoil using k-kl-omega model

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Old   July 16, 2019, 10:20
Default Transition over airfoil using k-kl-omega model
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Antoine
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Hi !

For my project I'm supposed to study the flow transition from laminar to turbulent around an aerofoil of a racing car.

I've done several analysis using the k-kl-omega model on FLUENT and the thing is, I don't know which variable is the most accurate to say where the transition occurs on the aerofoil...

Should I use the Cp plot, the turbulent viscosity plot, the specific dissipation rate (omega) plot or the turbulent kinetic energy plot ?

And also, is the eddy viscosity contour good to get an idea of where the transition occurs ?

Thank you for your help.

Antoine

PS: I have attached some of the plot and contour I did for a k-kl-omega analysis using a 8deg angle of an Eppler-387 aerofoil.
Attached Images
File Type: png eddy-viscosity_8deg_k-kl-omega.PNG (48.5 KB, 9 views)
File Type: png pressure-plot_8deg_k-kl-omega.PNG (19.7 KB, 7 views)
File Type: png 8deg_turbulent-viscosity.PNG (18.6 KB, 5 views)
File Type: png 8deg_turbulent-kinetic-energy.PNG (21.1 KB, 6 views)
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Old   July 16, 2019, 11:12
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Isn't there an intermittency factor which tells you whether the flow is laminar or turbulent, with values between 0 and 1 representing the transition region?


transition isn't a binary trait, it is a phenomenon. Each of these variables can be used to define a transition (each in a different kind of sense).
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Old   July 17, 2019, 05:21
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Thank you for your answer !

Well, I have actually heard about this intermittency factor on Fluent but I haven't been able to make it work...

Do you know how to set it up ?
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