SEMINAR: Low-Dimensional, Time Delay Models of Unsteady Aerodynamics and Feed-Forward Control

Abstract:

Different versions of time delay and decay models have been used to model unsteady aerodynamics and the effects of actuation on the lift of maneuvering airfoils. Recent measurements at Technion of the lift coefficient history obtained from a NACA 0018 airfoil undergoing pitching maneuvers with blowing-type active flow control were used to obtain low-dimensional models for control. Disturbance models for the lift response to pitching at different steady state blowing amplitudes were identified based on a variation of the Goman-Khrabrov model. A different model for the plant that represents the lift response to sinusoidal blowing amplitude had the form of a time-delay system. The two models were used to design a feed-forward controller. The ability of the controller to compensate for lift oscillations during pitching maneuvers was evaluated using a Simulink model.

Biography:

Dr. David Williams is a professor of Mechanical and Aerospace Engineering at Illinois Institute of Technology in Chicago, where he has been employed for 34 years. He is a research fellow of the Alexander von Humboldt Foundation in Germany, a Fellow of the American Physical Society, and an Associate Fellow of AIAA. In 2018 he was awarded IIT’s university Excellence in Teaching Award. His research focuses on unsteady aerodynamics and closed-loop active flow control.