An Overview of Static and Dynamic Airfoil Performance

An overview was constructed from available experimental data for static and dynamic stall characteristics of airfoils operating at low speeds. Emphasis was given to the history of changes in the boundary layer development. Separation and stall types were revisited to understand the physics involved with stall hysteresis. Fixed and variable speed, and dynamic stall hysteresis were studied. The study reveals the need to extend the parametric studies of single airfoils to multi-element airfoils. This is evident from wind tunnel tests of a flapped airfoil. Flap deployment brings the low Reynolds number hysteresis phenomenon back to the airfoil operating at relatively high test Reynolds number.