Seminar: Active Control of High-Speed Turbulent Flows Using Excitation of Instabilities

Abstract

Flow control is typically used to manipulate a flow’s natural behavior in order to minimize its adverse and maximize its favorable effects on a vehicle or a system. When active flow control (AFC) is used in aerospace applications, the actuation can be turned on/off or adapted on demand as the flight conditions are changed. AFC techniques that can provide significant gain over a large range of flow/flight conditions with relatively small cost or penalty are the most preferred ones. Flows with Kelvin-Helmholtz instability, which are present in many applications, are perfect candidates for using such a control technique and have been the subject of research for over five decades. However, the control had been limited to low-speed flows in the earlier decades due to the limitations of the available actuators. The recent development of plasma actuators that are capable of producing high-amplitude and high-bandwidth thermal perturbations suitable for excitation of K-H instabilities has extended the application of such control to high-speed and high-Reynolds number flows of interest in aerospace applications. K-H instability and two classes of these plasma actuators, localized arc filament plasma actuators (LAFPAs) and nano-second dielectric barrier discharge (NS-DBD) plasma actuators, will be briefly discussed in this seminar. Capabilities and control authorities of these two actuators, and their tremendous benefits will be presented and discussed in two very different flows.

About the speaker

Professor Samimy is the John B. NordholtProfessor of Mechanical and Aerospace Engineering and the founding director emeritus of the Aerospace Research Center. His interests are in turbulent flows, flow and aeroacoustics physics and control. He has educated a large number of engineers and scientists who are currently in various academic positions, national laboratories and industry. He has served on numerous national committees and editorial boards and has lectured extensively in the U.S. and abroad. He is a fellow of four major societies: AIAA, ASME, APS and AAAS. He has received numerous awards, including, the College of Engineering Clara and Peter Scott Faculty Award for Excellence in Engineering Education, Alumni Distinguished Graduate Faculty Award for Student Mentoring and Ohio State’s Distinguished Scholar Award. The University Distinguished Scholar Award, one of the highest awards within the university, recognizes and honors six faculty members each year, from all the fields and from over two thousand faculty, who have demonstrated scholarly activity, research or other creative works which represent exceptional achievements in their fields.

Hosted by Professor Jim Gregory.