Why am I seeing extremely high L/D ratio of (e.g. L/D = 90) in my 2D airfoil analysis?

Can anyone explain/justify why, using the 'Theory of Wing Sections' by ABBOTT the lift/drag ratios seem so high. For example, I'm doing an analysis of the NACA0012 airfoil and using their experimental data on pg462/463 at 8 degrees CL is roughly 0.9 and CD is roughly 0.001 giving a lift/drag ratio of 90. This seems incredibly high since as far as I'm aware lift/drag ratios go up to 70 to 75 practically from answers I've seen on here. My problem is that my CFD analysis also gives these high lift/drag ratios but I just didn't think it was possible.

Thanks in advance to anyone who can help!

• I would replace "possible" with "practical" Commented Mar 3, 2021 at 19:54
• Could you be looking at lift/*parasite* drag only ratios? Induced drag depends on span only, so probably isn't included in 2-D section analysis. Commented Mar 3, 2021 at 19:58
• @JanHudec yeah I suppose it could be that not all the drag is included since it's a 2D airfoil, are airfoil L/D g ratios generally larger then? Commented Mar 3, 2021 at 20:20
• @Barnaby, the lift is approximated well by the 2-D analysis, so if any form of drag is not calculated, the L/D will obviously be higher than the final 3-D wing. Commented Mar 3, 2021 at 20:28