[amir_14]

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?

[cfd seeker]

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

[amir_14]

Originally Posted by cfd seeker

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

[amir_14]

[Sixkillers]

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?

[amir_14]

Originally Posted by Sixkillers

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.