Larry Dunn

Thank you!

I'm new to this, and just started playing with XFLR5. I'm getting some Cl/Cd polars that I dont understand. I've attached a pic. I'm wondering how you can have two different Cd values for the same Cl? This only seems to happen at higher Cl numbers, but I see the same thing when I look at the polars on the Airfoiltools website. Is this some sort of artifact or something else? Thanks, Larry