This project investigates aerodynamic system identification. An airfoil produces time varying loads based on the current and past boundary conditions; this project seeks to identify the lift loads resulting from pitch motion.
The first part discusses some unsteady aerodynamic theory. The second part discusses the identification process. The final part discusses conclusions and observations.

A Box-Jenkins model successfully modeled the lowand moderate airfoil reduced frequencies, but was  troublesome at higher frequencies. Interestingly, the Theodorsen theory qualitatively matches the CFD results except above approximately a reduced frequency of unity. The moderate frequency lift deficiency predicted by Theodorsen was found in the CFD solution and the Box-Jenkins model. Interestingly, as the high frequencies were resolved, the system appears more distributed. The final Box-Jenkins model accurately predicted the forces resulting from a validation input signal.

Bode Frequency Response of Data and Box-Jenkins Model

The project document is at sifinal.pdf.