Lecture Title: Reactive Control of Bypass Boundary Layer Transition Using Plasma Actuators
Speaker Name & Title: Dr. Ahmed Naguib
Professor of Mechanical Engineering
Michigan State University
Special Lecture Series: AE585 Seminar
Sponsoring Department: AERO
http://www.engin.umich.edu/aero

Lecture Abstract: The transition of a boundary layer from laminar to turbulent state bypasses the classical TollmienSchlichting path in the presence of heightened levels of freestream turbulence. Such transition takes place, for example, on the turbine blades of gasturbine/jet engines, profoundly affecting the heating of the blades by the combustor exhaust gases and therefore the overall efficiency of the engine. The bypass transition process is initiated via the formation of lowspeed streaks which grow in strength with downstream distance and eventually become unstable, leading to the formation of turbulent spots. Over the past few years we have carried out a systematic series of investigations aimed at evaluating the capability of a plasmaactuatorbased feedforwardfeedback control system to weaken streaks induced “synthetically” in a Blasius boundary layer via dynamic roughness elements. In this model problem, the control system is implemented within a streamwise domain where the streaks exhibit linear growth. At the upstream and downstream end of the domain feedforward and feedback wallshearstress sensors are utilized. The output from the sensors is fed to appropriately designed controllers which drive plasma actuators providing wallnormal forcing to oppose the streaks. In this presentation, details of the control effort in the model problem will be described along with the corresponding results assessing the viability of the control approach. Additionally, recent results will be presented on implementation of the control system in a boundary layer beneath a turbulent freestream, where the streaks form stochastically.

Speaker Bio: Ahmed Naguib is currently Professor in Mechanical Engineering at Michigan State University. He served as the Associate Chair for the Graduate Program from 2012 to 2014. His BS degree is from Ain Shams University, Cairo Egypt, and Master and Ph.D. degrees are from Illinois Institute of Technology, Chicago, USA. His research interests are in experimental fluid dynamics and associated applications, particularly in the field of turbulence and flow instability physics and control, unsteady aerodynamics as well as development of measurement techniques. Prof. Naguib’s work has resulted in more than seventy conference and journal publications, two book chapters, and three patents. He has also been an Associate Editor of the American Institute of Aeronautics and Astronautics (AIAA) Journal since January 2009 and he was awarded the AIAA Associate Fellow grade in 2012.
https://www.egr.msu.edu/people/profil...