Development of a Pulsed Combustion Actuator 43 rd AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada, 10 - 13 Jan 2005. AIAA-2005-1084 For High-Speed Flow Control Andrew. D. Cutler * The George Washington University, Hampton, VA, 23666 B. Terry Beck † Kansas State University, Manhattan, KS, 66506 Jennifer A. Wilkes ‡ The College of William and Mary, Williamsburg, VA, 23187 and J. Philip Drummond § , David W. Alderfer ** , and Paul M. Danehy †† NASA Langley Research Center, Hampton, VA, 23681 This paper describes the flow within a prototype actuator, energized by pulsed combustion or detonations, that provides a pulsed jet suitable for flow control in high-speed applications. A high-speed valve, capable of delivering a pulsed stream of reactants—a mixture of H 2 and air—at rates of up to 1500 pulses per second, has been constructed. The reactants burn in a resonant chamber, and the products exit the device as a pulsed jet. High frequency pressure transducers have been used to monitor the pressure fluctuations in the device at various reactant injection frequencies, including both resonant and off-resonant conditions. The combustion chamber has been constructed with windows, and the flow inside it has been visualized using Planar Laser-Induced Fluorescence (PLIF). The pulsed jet at the exit of the device has been observed using schlieren. I. Introduction A. Background OUNDARY layer control can be broadly classified into passive and active control 1 . Common applications include the control of boundary layer separation in external flows to maintain the effectiveness of flaps and other control surfaces, and internal flow boundary layer control associated with the operation of jet engine inlet and diffuser flows. Passive control includes the use of common devices such as vortex generator tabs 2 to delay the onset of boundary layer separation. Active control includes the many leading and trailing edge devices used in conjunction with flow control over wing surfaces 3 . B Actuators of various types play an important role in active boundary layer control. A variety of different actuator devices have previously been investigated as flow control devices for both internal and external boundary layer applications. The operating principles for such devices are typically based on either mechanical deflection, mass injection, or the use of synthetic jets 4 . Mechanical actuator devices include conventional flap controls, as well as more recent MEMS flap devices. Mass injection actuators are characterized by a net mass flow through the * Associate Professor, MAE Dep’t, 303 Butler Farm Rd. Suite 101A, Associate Fellow AIAA † Professor, Dep’t of Mechanical & Nuclear Eng., 302 Rathbone Hall. ‡ Graduate Student, Dep’t of Physics, P.O. Box 8795, Student Member AIAA. § Senior Research Scientist, Hypersonic Air Breathing Propulsion Branch, MS 168. Associate Fellow AIAA ** Electronics Engineer, Advanced Sensing and Optical Measurement Branch, MS 236. †† Optical Physicist, Advanced Sensing and Optical Measurement Branch, MS 236. Associate Fellow AIAA American Institute of Aeronautics and Astronautics 1 Copyright © 2005 by the American Institute of Aeronautics and Astronautics Inc. The U.S. Government has a royalty-free license to exercise all rights under the copyright claimed herein for Governmental purposes. All other rights are reserved by the copyright owner.