Interactive Airfoil Analysis


Introduction

The program built into this page allows you to experiment with the effect of airfoil shape and angle of attack on the pressure distribution.


Instructions

Click on the top part of the plot to increase the angle of attack; clicking on the lower portion reduces alpha. Drag the handles shown on the upper or lower surfaces to modify the shape of the section and watch the effects on Cp.

Suggested Exercises

Change the airfoil thickness and note the effect on upper and lower surface pressures. Notice how thickness affects the Cp at the trailing edge. Create a pressure peak near the nose on the upper or lower side by changing the angle of attack. Change the camber near the nose to remove the pressure peak. Try to create a positive pitching moment section, a very thin, highly cambered section, and a symmetrical section.

Technical Details

This program uses a combination of thin airfoil theory and conformal mapping to very quickly compute pressures on an airfoil. A method like this was used in the 1950's to compute airfoil pressure distributions before Java was invented. The section shape is very simple as well: upper and lower surfaces consist of a quadratic in sqrt(x) and a quadratic in (1-x), patched together at the control points. This provides just 4 degrees of freedom, but does lead to curves that look like airfoils.