Events Calendar

Aerospace and Mechanical Engineering Seminar Series

Speaker: Kevin K. Chen , Viterbi Fellow in the Department of Aerospace & Mechanical Engineering at the University of Southern California, Los Angeles, CA

Talk Title: Low Mach Number Simulation of Turbulent CombustionOptimal Actuator and Sensor Placement for Feedback Flow Control

Series: Aerospace and Mechanical Engineering Seminar Series

Abstract: Feedback control has an enormous potential to manipulate fluid flows in desirable ways. It may one day effect, for instance, a significant improvement in vehicle performance and efficiency. One fundamental question has remained unanswered, however: where should the feedback system's actuators and sensors be located in the flow? The state of the art is shockingly insufficient; the vast majority of flow control studies use trial and error, or otherwise flawed heuristics.
In this seminar, we will explore why some actuator and sensor placements are more effective than others. Specifically, we will examine the optimal control of the Ginzburg-Landau and Orr-Sommerfeld/Squire equations, using localized actuators and sensors. By implementing a novel algorithm for the gradient of a control performance measure with respect to actuator and sensor positions, we can iterate efficiently toward optimal positions in these fluid flow models. The control theoretical and physical interpretations of the optimal placements yield a set of heuristics that may help control designers predict effective actuator and sensor placements. In particular, we will discuss the respective pros and cons of heuristics based on fundamental control limitations, eigenmodes, sensitivity to spatially localized feedback, optimal growth, and impulse responses.

Biography: Kevin Chen is presently a Viterbi Postdoctoral Fellow at the University of Southern California, in the Aerospace and Mechanical Engineering department. He attended Caltech as an Axline Scholar, where he received a B.S. with Honor in Engineering and Applied Science, with a focus in Aeronautics, in 2009. At Caltech, he conducted research in experimental and computational fluid dynamics with Mory Gharib, Beverley McKeon, and Tim Colonius. He attended Princeton University as a Gordon Y. S. Wu fellow, where he received an M.A. and a Ph.D. in Mechanical and Aerospace Engineering in 2011 and 2014, respectively, under the advising of Clancy Rowley and Howard Stone. He has received support from the Barry M. Goldwater Scholarship, the DOD NDSEG and NSF GRFP fellowships, and awards from Caltech and Princeton University. Kevin's primary research interest is the development of feedback flow control, where fluid mechanics intersect with modern control theory, stability theory, dynamical systems, and computational methods.

Host: Paul Ronney

Location: Seaver Science Library (SSL) - 150

Audiences: Everyone Is Invited

Contact: Valerie Childress