[hikarilgy]

Hi, I am encountering some problems while simulating airfoil with vortex generators in Star CCM+. I really need some help. Thank you.
As you can see, there is some weird vortex shedding from one side of VGs. Current AoA is 14deg, Cl just drops comparing previous AoA. From my experiense, stall is not supposed to be happened at this AoA. Besides, the phenomenon does not seems like stall. So I think this may be due to incorrect prism layer setting, but I don't know where is the problem.
For the geometry parameters, the chord of airfoil section is 2.17m, and span is 0.3m. VG height is 0.015m. located at 40% of the chord.
For the mesh parameters, I am using advancing layer mesher, prism layer total thickness of airfoil is 0.034m, number of layers is 36. for VGs, they are 0.00115m and 20 layers. surface growth rate is 1.08. Mesh quality is pretty good. Volume Change over 0.1 is about 99.129%.
For the boundary condition, velocity inlet , pressure outlet and symmetry plane are applied, flow speed is about 27m/s.
For the turbulence model, I am using k-omega and gamma-retheta transition model, turning on cross flow terms, free stream edge is 0.034m, constant density, turbulent and steady.
mesh1.jpg

mesh2.jpg

mesh3.PNG

mesh5.PNG

result2.jpg

[hikarilgy]

In case anyone would ask, I have solved it. It turns out the boundary condition problem. Instead of symmetry plane, periodic boundary condition works.

[bonans]

Hi hikarilgy,
I am currently working on a simulation regarding serrated trailing edges. I need to set up the same simulation as you did: basicallY an extrusion of the airfoil profile without wing tip effects.
Did you just made the extrusion of your profile without filling the extremities and then you created the WT as narrow as the airfoil, attached to it, leaving the airfoil empty?
See the attachments for what I have done.
Did you then creaded an automated mesh 3D?
I have tried to do so but I had trouble doing the subtract since i had a unique cad (airfoil+WT). I even tried to set up a Badge 2d meshing but I ended up with a 2d sim, which I don't want.
How did you impose the periodic condition, would you please guide me through it?
Thank you very much