Linear unsteady aerodynamic models from wind tunnel measurements

S. L. Brunton, C. W. Rowley, and D. R. Williams

AIAA Paper 2011-3581, 41st Fluid Dynamics Conference and Exhibit , June 2011.


Linear unsteady aerodynamic models are obtained for a NACA 0006 airfoil in a wind tunnel experiment at Reynolds number 65,000. A family of system identification maneuvers, based on a canonical step-up, hold maneuver, are specifically designed to extract relevant unsteady information from phase averaged wind tunnel measurements. Linear models based on these maneuvers are constructed using OKID/ERA for the case of pitching about 0 degrees and 10 degrees, as well as the case of pure plunge. It is shown that the identified models are more accurate than Theodorsen's model for all maneuvers, especially those at larger base angle of attack.

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