airfoil lift and drag coefficient
 

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 !:(

http://img4up.com/up2/12426092741833649440.jpg

can everybody help me?:(

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

http://img4up.com/up2/95355975160838392917.jpg

http://img4up.com/up2/41789434038302271552.jpg

http://img4up.com/up2/62569138080709307790.jpg

http://img4up.com/up2/15325669415822876946.jpg

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.