Event
AE Seminar | Control of Instabilities in Reactive and Non-Reactive Flowfields
Wednesday, February 11, 2015
3:30 p.m.
3164 Martin Hall | Aerospace Engineering Conference Room
Chris Cadou
cadou@umd.edu
http://www.aero.umd.edu/events/seminars
Aerospace Engineering Minta Martin Seminar Series
CONTROL OF INSTABILITIES IN REACTIVE AND NON-REACTIVE FLOWFIELDS
Speaker: Professor Ann R. Karagozian (ark@seas.ucla.edu)
UCLA Mechanical & Aerospace Engineering Department
Abstract:
There is a remarkable range of physical phenomena that are foundational to the successful development of efficient, robust energy and propulsion systems. Understanding and potentially controlling such fundamental phenomena can have a profound benefit for these types of engineering systems. This talk will describe research at UCLA on flow and combustion instabilities and their control, in the spirit of this fundamental approach. Focus will be placed on acoustically-coupled combustion processes associated with condensed-phase fuels, as well as the gaseous jet in crossflow, including its shear layer stability characteristics and their control. Interrogation of these rather disparate yet canonical engineering flowfields involves use of experimental diagnostics that reveal heretofore unexplained phenomena. In the problem of an acoustically-driven, burning liquid fuel droplet, phase-locked OH* chemiluminescence imaging reveals a mean (bulk) level of coupling as well as a dynamical coupling between acoustics and reactive processes that have implications for combustion instabilities in a range of propulsion devices. For the jet in crossflow, exploration of shear layer instabilities via acetone PLIF, stereo PIV, and hot wire anemometry enable the determination of flow conditions causing a transition from convective to absolute instability, with attendant alterations in jet structure and the implications for control of energy-efficient devices.
Bio: Ann Karagozian has been a Professor in the Department of Mechanical and Aerospace Engineering at UCLA since 1982. Her research interests lie in fluid mechanics and combustion as applied to improved engine efficiency, reduced emissions, alternative fuels, and advanced air breathing and rocket propulsion systems. Professor Karagozian is a Past Chair of the American Physical Society/Division of Fluid Dynamics as well as a Past Chair of the UCLA Academic Senate. She was a member of the Air Force Scientific Advisory Board for nearly a dozen years, twice receiving the Air Force Decoration for Exceptional Civilian Service, serving as Vice Chair (2005-2009), and chairing numerous technical studies, including a 2006 study on Air Vehicle Fuel Efficiency and a 2010 study on Future Launch Vehicles. She is a Fellow of APS, AIAA, and ASME, and was recently a 2013-14 Midwest Mechanics Seminar speaker. She received her B.S. in Engineering from UCLA in 1978 and her M.S. and Ph.D. in Mechanical Engineering from the California Institute of Technology in 1979 and 1982, respectively. More information on Karagozian’s Energy and Propulsion Research Laboratory (EPRL) may be found at http://www.seas.ucla.edu/combustion/ and information on the newly established AFRL-UCLA Collaborative Center for Aerospace Sciences (CCAS) may be found at http://ccas.seas.ucla.edu/index.html.
