UweSchuster
commented
2 years ago Hi Phil,
Thank you for your message. I am currently travelling and have no access to a computer but here are some notes to help: Aeolus does compute the AOA to provide the target design lift. The 3x AOA you can enter are just the support points for the interpolation. In the Cl,Cd results table you will however find the cl cd values for these support AOAs as well as for the final AOA. For discretization, i propose at least 48 panels in the circumferential direction and an aspect ratio of at least 0.3 for all strips. Hope this helps!
Best regards,
Uwe
On Apr 24, 2022 at 7:58 PM, <Philippe Manzano @.***)> wrote:
Hello, I'm learning Aeolus basic functions and validate simple profiles with Xfoil, Javafoil and Nasa FoilSim website https://www.grc.nasa.gov/WWW/K-12/airplane/foil3.html : An ellipse 20% thickness with a 2.5m span and a 0.1m chord @ 3.94444 m/s.
FoilSim (2D-3D), Xfoil (2D) and Javafoil (2D) roughly get the same result for Cl and Cd: (https://user-images.githubusercontent.com/65325/164988758-cfde1362-737e-4d82-991b-02201c5f4f09.png) (https://user-images.githubusercontent.com/65325/164988773-446afe7f-35d9-46b3-b590-45adebf42b92.png) (https://user-images.githubusercontent.com/65325/164989650-a27b4429-5852-4443-8ebd-5b6cbde292cc.png)
Entered Reynolds number is from Aeolus (freshwater). I imported the same profile in Aeolus (first time with a 110 points profile, and the second one with a 48 points profile)
First, I can't tell Aeolus to stick to AoA 6.3: Despite choosing AoA1, 2 and 3 as 6.3, it keeps returning a resulting AoA of 9.997° Even with default -3,5,10° it doesn't get the right AoA around 6.3° but sticks to 9.997° There's a warning saying it has bad convergence despite smoothing discretization, both with 111 and 48 points. I find it pretty slower than for other profiles (10 cores result in 25s) even for a simple 48 points dat profile.
How to only compute one AoA? Any idea why it's not converging and slower than usual? Maybe it's related? Do you have hints to validate this kind of profile?
I attach my Aeolus file and both ellipses dat files ellipses.zip (https://github.com/AeolusAero/Aeolus-AeroSketchPad/files/8550224/ellipses.zip)
Thank you very much and have a great week.
Phil
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j2l
Aspect ratio is far beyond 0.3
Hello, I'm learning Aeolus basic functions and validate simple profiles with Xfoil, Javafoil and Nasa FoilSim website https://www.grc.nasa.gov/WWW/K-12/airplane/foil3.html : An ellipse 20% thickness with a 2.5m span and a 0.1m chord @ 3.94444 m/s.
FoilSim (2D-3D), Xfoil (2D) and Javafoil (2D) roughly get the same result for Cl and Cd:
Entered Reynolds number is from Aeolus (freshwater). I imported the same profile in Aeolus (first time with a 110 points profile, and the second one with a 48 points profile)
First, I can't tell Aeolus to stick to AoA 6.3: Despite choosing AoA1, 2 and 3 as 6.3, it keeps returning a resulting AoA of 9.997° Even with default -3,5,10° it doesn't get the right AoA around 6.3° but sticks to 9.997° There's a warning saying it has bad convergence despite smoothing discretization, both with 111 and 48 points. I find it pretty slower than for other profiles (10 cores result in 25s) even for a simple 48 points dat profile.
How to only compute one AoA? Any idea why it's not converging and slower than usual? Maybe it's related? Do you have hints to validate this kind of profile?
I attach my Aeolus file and both ellipses dat files ellipses.zip
Thank you very much and have a great week.
Phil