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cd and dl on an airfoil

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Old   November 5, 2019, 15:33
Default cd and dl on an airfoil
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Joan Vilalta Mor
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Hi,
I'm doing a research project about the aerodynamics in a F1 car and I'm doing an airfoil simulation to get the drag and lift coefficient and forces in ANSYS Fluent
I have already done the geometry and an hexa/prism mesh of the airfoil
This is the geometry:
1.png
And this is the mesh:
2.png3.png

Now my questions are:
Do I have to use a laminar air or a turbulent model (such as k-epsilon)?
Would you chose an hybrid or an standard initialization?
What number of iterations would you select to run the calculation?

Cheers
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Old   November 5, 2019, 17:30
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Matt
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you will definitely need a turbulence model and the number of iterations should be selected so that your figures of merit (lift and drag) and residuals converge.

initialization shouldn't matter much in the final solution, but can affect how quickly you get there... assuming you aren't initializing in way that makes no sense physically.
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Old   November 5, 2019, 18:16
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Joan Vilalta Mor
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Quote:
Originally Posted by fluid23 View Post
you will definitely need a turbulence model and the number of iterations should be selected so that your figures of merit (lift and drag) and residuals converge.

initialization shouldn't matter much in the final solution, but can affect how quickly you get there... assuming you aren't initializing in way that makes no sense physically.
Why is it so important to do the simulation with a turbulent model rather than a laminar?
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Old   November 5, 2019, 19:25
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Quote:
Originally Posted by Joan Vilalta View Post
Why is it so important to do the simulation with a turbulent model rather than a laminar?


The flow around an F1 car is not laminar. I know you are only looking at the airfoil, but there is bound to be turbulent boundary layer at any practical Reynolds number. Boundary layer separation will definitely be affected by your choice (or lack) of turbulence model.

If you want your results to represent reality in any meaningful way you should not only use a turbulence model but understand why itís the best choice of the available options.
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