aerofoil simulations 2D and 3D problems

itskarimz · July 24, 2019, 21:27

Greetings,
(this is my first post and i hope i do not offend anyone, if i break rules by any chance)
I am simulating in 2D and 3D for NACA 65(2)-415 aerofoil, and the results i am receiving are not satisfactory.
i am hoping of reaching stall, therefore the physics model used is the Menter SST K-omega turbulence model, with gamma transition.
in 2D the coefficient of lift i am getting is higher than expected.
the main problem lies in 3D
even when in the vector scene backflow and vortex formation are noticed, which is a characteristic sign of stall, the coefficient of lift does not drop, but continues increasing.
in addition to this stall is much delayed, in terms of angle of attack
the mesh used is polyhedral mesh, with prism layers, with two volumetric mesh refinements nearer the wing.
any advice is appreciated as this is for a masters project due in the next month
thank you in advance
karim

me3840 · July 28, 2019, 17:55

Aero problems like this are usually mesh related, please post pictures of your mesh.

If you think the Cl should be dropping based on what the field looks like, but the report disagrees, are you sure the report is set up correctly?

July 24, 2019, 21:27	aerofoil simulations 2D and 3D problems	#1
itskarimz New Member County (optional) Join Date: Jul 2019 Posts: 1 Rep Power: 0	Greetings, (this is my first post and i hope i do not offend anyone, if i break rules by any chance) I am simulating in 2D and 3D for NACA 65(2)-415 aerofoil, and the results i am receiving are not satisfactory. i am hoping of reaching stall, therefore the physics model used is the Menter SST K-omega turbulence model, with gamma transition. in 2D the coefficient of lift i am getting is higher than expected. the main problem lies in 3D even when in the vector scene backflow and vortex formation are noticed, which is a characteristic sign of stall, the coefficient of lift does not drop, but continues increasing. in addition to this stall is much delayed, in terms of angle of attack the mesh used is polyhedral mesh, with prism layers, with two volumetric mesh refinements nearer the wing. any advice is appreciated as this is for a masters project due in the next month thank you in advance karim

July 28, 2019, 17:55		#2
me3840 Senior Member Join Date: Nov 2010 Location: USA Posts: 1,232 Rep Power: 25	Aero problems like this are usually mesh related, please post pictures of your mesh. If you think the Cl should be dropping based on what the field looks like, but the report disagrees, are you sure the report is set up correctly?