Incorrect Cl and Cd data for a 3D airfoil

araina85 · November 13, 2014, 11:13

I am trying to model a 3D airfoil i.e. an infinite airfoil section to obtain and compare the lift and drag coefficients to that obtained from 2D. In principle, the 2D and 3D data should match. I am under-predicting the lift by ~50% and over-predicting drag by ~60%. I was using a k-w SST model for my simulations.

Given the incorrect results, I went back and simulated the 3D airfoil assuming no viscosity (inviscid solution). But even this solution provides me with a cl that is lower than the viscous experimental data.

Any ideas as to what I am doing wrong?

I could attach my case files if required.

HyperNova · November 13, 2014, 13:31

Did you define the project area correctly ?

araina85 · November 13, 2014, 15:09

yes. I have a 1m chord with a 1m depth.

November 13, 2014, 11:13	Incorrect Cl and Cd data for a 3D airfoil	#1
araina85 New Member raina Join Date: Oct 2014 Posts: 2 Rep Power: 0	I am trying to model a 3D airfoil i.e. an infinite airfoil section to obtain and compare the lift and drag coefficients to that obtained from 2D. In principle, the 2D and 3D data should match. I am under-predicting the lift by ~50% and over-predicting drag by ~60%. I was using a k-w SST model for my simulations. Given the incorrect results, I went back and simulated the 3D airfoil assuming no viscosity (inviscid solution). But even this solution provides me with a cl that is lower than the viscous experimental data. Any ideas as to what I am doing wrong? I could attach my case files if required.

November 13, 2014, 13:31		#2
HyperNova Senior Member B_Kia Join Date: May 2014 Location: Ir Posts: 123 Rep Power: 12	Did you define the project area correctly ?

November 13, 2014, 15:09		#3
araina85 New Member raina Join Date: Oct 2014 Posts: 2 Rep Power: 0	yes. I have a 1m chord with a 1m depth.