MMAE Seminar by Louis N. Cattafesta III: Adaptive Separation Control of a Laminar Boundary Layer using Online Dynamic Mode Decomposition

Armour College of Engineering’s Department of Mechanical, Materials, and Aerospace Engineering will welcome Louis Cattafesta, a University Eminent Scholar and professor in the Department of Mechanical Engineering at the Florida State University, to present a lecture, “Adaptive Separation Control of a Laminar Boundary Layer using Online Dynamic Mode Decomposition.”

The seminar will take place on Wednesday, February 23, 2022, from 12:45–1:45 p.m. in RE-104. It is open to the public. Contact Elena Magnus at magnus@iit.edu for the seminar details.

Abstract

Adaptive control of flow separation based on online dynamic mode decomposition (DMD) is formulated and implemented on a canonical separated laminar boundary layer via a pulse-modulated zero-net mass-flux (ZNMF) jet actuator located just upstream of separation. Using a linear array of 13 flush-mounted microphones, dynamical characteristics of the separated flow subjected to forcing are extracted by online DMD. This method provides updates of the modal characteristics of the separated flow while forcing is applied at a rate commensurate with the characteristic time scales of the flow. In particular, online DMD provides a time-varying linear estimate of the nonlinear evolution of the controlled flow without any prior knowledge. Using this adaptive model, feedback control is then implemented in which the Linear Quadratic Regulator gains are computed recursively. This physics-based, autonomous approach results in more efficient  flow reattachment, requiring approximately 30 percent less actuator effort compared with commensurate open-loop control. Four Reynolds numbers are tested to assess robustness, Re_c = 0.9x10⁵, 1x10⁵, 1.1x10⁵, and 1.25x10⁵. All controlled cases exhibit a significant reduction in mean separation bubble height, requiring approximately 10 characteristic time periods to establish control.

Biography

Louis N. Cattafesta III is currently a University Eminent Scholar and professor in the Department of Mechanical Engineering in the FAMU/FSU College of Engineering and previously served as the director of the Florida Center for Advanced Aero Propulsion (FCAAP) from 2017–2020. He received a B.S/ degree in mechanical engineering in 1986 from Penn State University, a M.S. degree in aeronautics from MIT in 1988 via an AFRAPT Fellowship, and a Ph.D. degree in mechanical engineering in 1992 from Penn State via a PSU College of Engineering Dean’s Fellowship and a NASA GSRP Fellowship. In 1992 he joined High Technology Corporation as a research scientist at NASA Langley Research Center. His research at NASA Langley focused on supersonic laminar flow control and pressure- and temperature-sensitive paint measurement techniques, and in 1996 he was awarded the 1996 NASA Team Excellence Award for his contributions. At that time, he became involved in active control of flow-induced cavity oscillations, which provoked his current research interests in active flow control and aeroacoustics.  He joined the University of Florida as an assistant professor in 1999 and was promoted to an associate and full professor in 2003 and 2008, respectively, before joining Florida State University in 2012. Funding for his research has been provided by grants from NASA, AFOSR, ONR, NSF, Boeing, Lockheed-Martin, General Electric, and Gulfstream, among others. Cattafesta has co-authored four AIAA best conference paper awards in 2001, 2002, and two in 2004. He is the author or co-author of seven United States patents, seven book chapters, and more than 100 archival journal publications. Cattafesta is a fellow of AIAA, APS, and ASME. He is also a member of ASA. He is currently an associate editor for Experiments in Fluids. Prior to this he was an associate editor for AIAA Journal.