NACA 4415 Airfoil Calculations

I recently performed an angle of attack (alpha) sweep for the NACA 4415 airfoil using a panel method. I compared my calculations with the wind tunnel experiment performed at the Ohio State University Aeronautical and Astronautical Research Laboratory 7x10 Subsonic Wind Tunnel. For the Reynolds Number=2x10^6 case, I found I could achieve excellent agreement with the uncorrected experimental data in the linear lift region if I reduced the experimental alpha by 0.7 degrees.

Has anyone else experience with this case?

Dear Sir
I also wish to perform simulations on the same profile. Can you suggest me few parameters or a topic of research on which simulation can be carried out as I am a new comer to this field and yet to start analysing performance of NACA4415 or some other profile blades whose experimental data is available online

Dear Barjinder,

I really don’t know what it is you are hoping to do, but if you are looking for a well-tested airfoil, I might suggest our S809 airfoil. It has been tested in several wind tunnels and it was also used on a 10m turbine and the entire system was tested in the gigantic wind tunnel at NASA’s Ames Research Center. We also offer polar predictions using the Eppler code that you can compare to.

You can find out more about our airfoils here:


Dear Mr. Buhl
I am doing Research in the Field of Wind energy, I need the information about the type of airfoils, which are suitable for Indian origin for Wind turbines, according to India’s Geographic location and environmental conditions and which profile is mostly used in India(Asia) for Wind turbine Blade fabrications. There are few companies in India like Suzlon Energy etc which are doing business in this field and commissioning wind turbines in India but they do not responding me well for my Research work. I want to find out i) A suitable turbulence model in CFD(Fluent) for Wind Turbine airfoil used in India, For the validation of CFD software results for validating Suitable Turbulence model, I need Experimental results by some of the Research Laboratory like NWTC ii) Study of airfoil characteristics at different angles of attack keeping wind velocity constant iii) variation of Lift and drag with velocity changes using CFD software. So I need the information about the airfoil used in India for Wind turbines.

Dear Barjinder,

I understand your frustration of trying to get detailed design information from manufacturers. I’ve had trouble even when they were working for us and we had signed non-disclosure agreements with them.

I have no idea what types of airfoils are used in India. The airfoils manufacturers use are more dependent on the size of the rotor, need for thick or thin airfoils, and whether it is a stall-regulated turbine or one that uses active controls. You can see which of our airfoils are suitable for different situations in this table: I suppose some manufacturers might choose different airfoils for different sites based upon wind speed and turbulence intensity, but I have no personal knowledge of that. I doubt that there are any India-specific airfoils.

As I mentioned earlier, the S809 airfoil is probably one of the most-tested wind-turbine airfoils in the world. It was designed for a small (<100kW), stall-regulated turbine. If you need something for a large, utility-scale turbine, I’m afraid I don’t have anything for you.

I cannot help you with choosing a turbulence model for your CFD simulations.