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-   -   subsonic Airfoil Flow (http://www.cfd-online.com/Forums/openfoam/67382-subsonic-airfoil-flow.html)

 husker August 13, 2009 09:33

subsonic Airfoil Flow

1 Attachment(s)
Hi to everyone,

I am studying on the flow around an airfoil at U=43 m/s and Reynolds=3E6.

I executed sonicFOAM NACA Airfoil tutorial for an example.

After I have read the User Guide, I understand that simpleFOAM can be used on steady-state laminar or turbulent problems. I activated the turbulence term and RANS model k-epsilon. The modified simpleFOAM files according to this problem are attached to this threat.

The problem is that the U, p contours are fully wrong as well as the coefficients of lift and drag.

I would like to hear some advices.

Regards,

 husker September 8, 2009 09:45

subsonic airfoil flow

hmm 85 views and no reply :(

Can anybody post an airfoil/wing subsonic flow tutorial with the FOAM files?

I think this may help many openFOAM beginners.

 husker September 10, 2009 04:21

subsonic airfoil flow

Is it an hard question?

 mkraposhin September 10, 2009 15:14

Can you post plots?

 walex September 14, 2009 07:21

Hi,

is your solution converged? How many iterations did you run? Are your Cd and Cl values still changing?

I also have problems to get the right forces. But my cp plot looks quite ok.

Alex

 husker September 15, 2009 07:31

Hi,

My solution never converges; Cd and Cl values change in a wide range interval.

I use "libforces.so" in order to print Cd, Cl and Cm. So I hope it is enough to give only directions to calculate the forces correctly.

Although flow around an airfoil at low AoAs is a basic problem on CFD topics, I am very suprised to see how hard it is with openFOAM.

 walex September 15, 2009 08:47

Hi,

you have to give the direction for Cd and Cl and also your refence area and your reference length and additionally the density. You also have to name the patch the forces shall be calculated for.

What kind of solver do you use? I will have a look if I can upload something later. Quite busy in the moment...

Alex

 husker September 17, 2009 09:08

Hi,

I agree with you about the reference values, directions and patch names. They are all ok.

I use parameters below:
simpleFOAM solver,
Newtonian transport model,
Realizable k-epsilon turbulence model,
Gridgen C-Mesh grid with yplus~1 sensitivity.

If you may find a chance to upload your simulation, it will be a good starting reference study for FOAM beginners like me.

 walex September 17, 2009 11:33

1 Attachment(s)
Hi,

I am checking the seetings from the airfoil2D tutorial right now and they deliver good results for my pressure forces and therefore also for my lift result. But the viscous forces blow up after a while. I am testing some other settings... But here are my current settings. Maybe they can help you.

 husker August 8, 2011 10:09

After so many months, thank you walex.

 murali March 3, 2013 18:17

sonicFoam/ras/nacafoil

hi

i am new here i didnt know about this solver and then the terms having the problem with the definition of the 0 folder because I don't know the exact meaning of the properties
alphat
mut
k
epilson
p
t and u

can any one help to know this solver

with regards

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