Ahmed Naguib | Plasma Actuators

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
www.engin.umich.edu/aero
Lecture Abstract: The transition of a boundary layer from laminar to turbulent state bypasses the classical Tollmien-Schlichting path in the presence of heightened levels of freestream turbulence. Such transition takes place, for example, on the turbine blades of gas-turbine/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 low-speed 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 plasma-actuator-based feedforward-feedback 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 wall-shear-stress sensors are utilized. The output from the sensors is fed to appropriately designed controllers which drive plasma actuators providing wall-normal 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.
www.egr.msu.edu/people/profil...

[@scienceminded]

Alternating layers of electromagnets or permanent magnets interacting with the discharge of the actuator array would provide a Lorentz force to enhance or modulate the partial vacuum generated on the control surface. Some of the energy of the wind rushing past the array could even be used to generate the force since the air becomes ionized.
I would like to see how a cone with an embedded coil in a wind tunnel where the tip of the cone is a negetive electrode with a high voltage discharge across a plasma bridge array ala the actuator to a ground near the base of the cone. The magnetic field would bend the path of the actuators charged particle stream outwards radially and then fold and twist around the cone, tightly coupling to the magnetic field.

[@chollingsworth9649]

WOW ! This is as I Imagined physics might be possible to be in dynamic plasma fluids

[@atomatopia1]

Although it seems that your PI feed forward control system worked very well I wonder if implementing a neural network would be able to improve the results.

[@matthiaslindner1874]

Has somebody investigated the peristaltic plasma waves with theoretical velocities up to 100m/s after Reece Roth?

[@ViceCoin]

Good for Hypersonic missiles.