Progress and prospects for active flow control using Microfabricated Electromechanical Systems (MEMS)

Abstract

An overview of selected current research on active flow control using Microfabricated Electromechanical Systems (MEMS) is presented. It is intended as a snapshot of research in progress and a look ahead rather than as a review of either active flow control or of MEMS applications to flow control. The central question is: Why MEMS? Why is this technology so important to active flow control? The question is addressed in two parts. In Part I, an unconventional perspective on the problem of active flow control is presented. It discusses the issue of microscale control of macroscale phenomena. The discussion sets a context for active flow control in terms of the degree of complexity of the flow, and relates the problem to the growing body of emerging ideas on complex systems. In Part II, a central objective is to raise the general level of awareness within the fluid mechanics community of MEMS technology and its potential and limitations in the context of active flow control. Examples of current research illustrate the technology and its impact on sensors, actuators and controllers. Three control problems illustrate some of the ideas developed in Part I, they are: active control of free jets, boundary layer control, and the control of aerodynamic forces on delta wings. PART L ACTIVE CONTROL AND COMPLEX SYSTEMS