Wrong Drag and Lift Coefficient when changing AoA

inspiron · November 19, 2013, 02:26

I'm trying to calculate Drag and Lift Coefficient of NACA 2415 airfoil. When flow with velocity of 10m/s passes over the airfoil with angle of attack (AOA) = 0, the CD and CL is as same as the data giving in Theory of wing sections.
Unfortunately, when I change the AOA, the result is terrible, even the CD is negative.

I try two model (k-e and SST) with Y+ calculated according to http://www.cfd-online.com/Tools/yplus.php ,but it does not change

Please give me some explain and solution for this problem

Thanks in advance.
PS: I attack my mesh for convenience http://www.mediafire.com/?498bgm94khh9bf1

misterdd · November 27, 2013, 14:00

recheck your drag calculation components in Monitors. Try to visualize the components according to your coordinate system.

November 19, 2013, 02:26	Wrong Drag and Lift Coefficient when changing AoA	#1
inspiron New Member Dinh Join Date: Sep 2013 Posts: 10 Rep Power: 13	I'm trying to calculate Drag and Lift Coefficient of NACA 2415 airfoil. When flow with velocity of 10m/s passes over the airfoil with angle of attack (AOA) = 0, the CD and CL is as same as the data giving in Theory of wing sections. Unfortunately, when I change the AOA, the result is terrible, even the CD is negative. I try two model (k-e and SST) with Y+ calculated according to http://www.cfd-online.com/Tools/yplus.php ,but it does not change Please give me some explain and solution for this problem Thanks in advance. PS: I attack my mesh for convenience http://www.mediafire.com/?498bgm94khh9bf1

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November 27, 2013, 14:00		#2
misterdd New Member misterdd Join Date: Dec 2012 Posts: 12 Rep Power: 13	recheck your drag calculation components in Monitors. Try to visualize the components according to your coordinate system.