Flow Control and Experimental Turbulence

Associate Professor P. Lavoie
Associate Director, Research
University of Toronto
Institute for Aerospace Studies
4925 Dufferin St., Ontario, Canada M3H 5T6

Phone:  +1-416-667-7716
Fax:  +1-416-667-7799
Email:  lavoie (at) utias.utoronto.ca
Web:  arrow.utias.utoronto.ca/~lavoie/

Education

  • Ph.D. – University of Newcastle
  • M.Sc. – Queen’s University
  • B.Sc. – Queen’s University

Research Overview

Prof. Lavoie’s research interests are in the fields of modern flow control and turbulence, primarily from an experimental perspective. He is particularly concerned with the study of transitional and turbulent flows, as well as the flow structures and instabilities associated with these phenomena. The focus of the FCET group is to investigate the fundamental dynamics of attached and separated shear layers, and how these can be manipulated to improve flow characteristics with respect to specific goals, such as skin-friction drag reduction and mitigating noise emissions. The overarching aim is to develop novel flow control strategies, based on modern approaches, and the instrumentation and tools required to implement passive or active control techniques in an experimental framework and real life applications, such as on the surface of an aircraft. The motivation at the core of this research is the reduction of greenhouse gas emission in commercial transport industries, in particular aviation, through improved fluid system efficiency.

One of the current projects is part of an ongoing international research effort, involving researchers from the US and the UK, aimed at addressing fundamental issues pertinent to the delay of boundary layer transition from laminar to turbulent state via model-based feedback control. This work, which is supported in part by Bombardier Aerospace and Pratt & Whitney Canada, has further significance for the implementation of active control of turbulent boundary layers. For this project, a model-based closed-loop control was developed and implemented to negate the transient growth instabilities, known to trigger early transition to turbulence, in a Blasius boundary layer. Recent tests in the FCET state of the art low-speed wind tunnel have demonstrated reduction of over 90% of the targeted disturbance energy.

Dielectric-barrier-discharge plasma actuators are being developed and utilized for the aforementioned flow control problem. In the context of the transition control problem, the electro-mechanical coupling provided by the plasma actuator is used to negate transient growth due to surface roughness, thus preventing transition. Plasma actuators are also used for the control of separated shear layers, such as those found in the wake of a landing gear or blunt trailing edge. The utilization of these actuators is also supplemented by the study of issues relating to the practical implementation of these devices in industry.

Finally, experimental investigations are presently underway to develop flow state estimators and low-order models for separation control. Estimators are essential tools in modern flow control to allow state estimation of the flow dynamics based on limited sensing. In addition, low-order models enable the implementation of robust control strategies with realistically feasible computational requirements, all of which supports the overarching objectives aimed at the practical implementation of flow control in industrial applications.