[andrelima]

I am doing flow analysis over 3d Wings with and without winglet on Ansys Fluent in order to decide which geometry reduce more my induced drag however, my CL and CD are not close to the analitycal values which I got from the Sadraey Polar drag method.

I have already tried both S-A and K-e methods. For the S-A I have set the the turbulence intensity of 1 % for the inlet and 5 % for the outlet. For the legth scale I have used the relation l=0.07*chord. For the K-e I have set the wall method as realizable and non-equilibrium wall trwatment. I've also set the same values for both turbulence intensity and length scale as the ones from S-A.

For Boundary conditions I've used 15 m/s for inlet and 0 gauge pressure for outlet.

I've also did a mesh convergence and got a mesh up to 8 millions cells and a erro of less than 1%, however I don´t know if this result is applicable considering that my results are not close to the analytical ones.

Anybody has a clue on which I could change? I don´t if I am seting the turbulence parameter correctly. Can anybody help?

[user01]

Originally Posted by andrelima

I am doing flow analysis over 3d Wings with and without winglet on Ansys Fluent in order to decide which geometry reduce more my induced drag however, my CL and CD are not close to the analitycal values which I got from the Sadraey Polar drag method.

I have already tried both S-A and K-e methods. For the S-A I have set the the turbulence intensity of 1 % for the inlet and 5 % for the outlet. For the legth scale I have used the relation l=0.07*chord. For the K-e I have set the wall method as realizable and non-equilibrium wall trwatment. I've also set the same values for both turbulence intensity and length scale as the ones from S-A.

For Boundary conditions I've used 15 m/s for inlet and 0 gauge pressure for outlet.

I've also did a mesh convergence and got a mesh up to 8 millions cells and a erro of less than 1%, however I don´t know if this result is applicable considering that my results are not close to the analytical ones.

Anybody has a clue on which I could change? I don´t if I am seting the turbulence parameter correctly. Can anybody help?

Hi!

This is Flow-3D forum. Your topic maybe fits better here. http://www.cfd-online.com/Forums/ansys/

About boundary conditions you used, have you tried to use outflow instead gauge pressure for outlet? Which are the dimensions of your enclosure? Have you check pressure waves? If the enclosure is small, gauge pressure = 0 can influence in the drag and lift...

Feel free to ask!

Regards.