Characterizing FLEET for Aerodynamic Measurements in Various Gas Mixtures and non-Air Environments
- Additional Document Info
- View All
© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. Femtosecond Laser Electronic Excitation Tagging (FLEET) has been developed recently (Michael, J., Edwards, M., Dogariu, A. and Miles, R., “Femtosecond laser electronic excitation tagging for quantitative velocity imaging in air,” Applied Optics, Vol. 50, No. 5158, 2011) to non-intrusively measure velocity, flow structure and temperature in unseeded air or pure nitrogen flows with a single laser and imaging system. The current study aims to investigate the technique in gas mixtures containing appreciable concentrations of argon, helium, carbon dioxide and oxygen. Signal strength, tagged line width and a wide variety of spectral features are presented in an effort to characterize FLEET in different environments and further the understanding of underlying physical mechanisms that change each of the measured quantities. Both temporally averaged and resolved spectra are obtained in tandem with single and multiple shot images from a high-speed CMOS camera at various delays and gates. Potential reaction pathways are summarized with special attention drawn to the interaction of metastable noble gases and molecular nitrogen which may lead to substantial amplification of the FLEET signal under certain conditions. The effect of tagged line features on uncertainty in velocity and temperature measurements is discussed along with methodologies to optimize the FLEET experimental apparatus relative to the composition of working fluid.
author list (cited authors)
Calvert, N., Zhang, Y., & Miles, R. B.