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airfoil lift and drag coefficient

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Old   December 31, 2012, 06:03
Default airfoil lift and drag coefficient
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amir
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hi dear friends
i have problem with modeling s809 airfoil
at low angle of attack i have large lift coefficient (200 times larger) and large negative drag coefficient & at high angle of attack i have large lift and drag coefficient.
also my pressure coefficient is large and inverse !



can everybody help me?
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Old   December 31, 2012, 12:45
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Have you scaled the mesh in fluent? Show your mesh, solver settings, boundary conditions, turbulence model then I will be able to suggest you something
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Old   January 1, 2013, 06:21
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Quote:
Originally Posted by cfd seeker View Post
Have you scaled the mesh in fluent? Show your mesh, solver settings, boundary conditions, turbulence model then I will be able to suggest you something
tanx dear cfd seeker
i found my mistake
it was at reference values
but my pressure coefficient is inverse still
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Old   January 1, 2013, 06:27
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Old   January 1, 2013, 06:58
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I think that the mesh has to be more finer in region of boundary layer to properly compute forces (drag/lift) acting on airfoil. What is your Y+? Have you consider usage of SST k-omega turbulence model?
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Old   January 1, 2013, 09:30
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Quote:
Originally Posted by Sixkillers View Post
I think that the mesh has to be more finer in region of boundary layer to properly compute forces (drag/lift) acting on airfoil. What is your Y+? Have you consider usage of SST k-omega turbulence model?
hi Sixkillers
i've adapted mesh near the wall so that y+ is Between 2 and 5 with Spalart-Allmaras Model.
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