Nitric oxide flow tagging in unseeded air.

A scheme for molecular tagging velocimetry is presented that can be used in air flows without any kind of seeding. The method is based on the local and instantaneous creation of nitric oxide (NO) molecules from N(2) and O(2) in the waist region of a focused ArF excimer laser beam. This NO distribution is advected by the flow and can be visualized any time later by laser-induced fluorescence in the gamma bands. The creation of NO is confirmed by use of an excitation spectrum. Two examples of the application of the new scheme for air-flow velocimetry are given in which single laser pulses are used for creation and visualization of NO.

[1]  P. A. Skaggs,et al.  Unseeded velocity measurement by ozone tagging velocimetry. , 1996, Optics letters.

[2]  L. Boedeker,et al.  Velocity measurement by H2O photolysis and laser-induced fluorescence of OH. , 1989, Optics letters.

[3]  M. Koochesfahani,et al.  Molecular Tagging Velocimetry (MTV) measurements in gas phase flows , 1999 .

[4]  R. Pitz,et al.  Ozone Tagging Velocimetry Using Narrowband Excimer Lasers , 1999 .

[5]  R. Wayne.  Chemistry of atmospheres - An introduction to the chemistry of the atmospheres of earth, the planets, and their satellites (2nd revised and enlarged edition) , 1987 .

[6]  Jürgen Wolfrum,et al.  NO-FLOW TAGGING BY PHOTODISSOCIATION OF NO2. A NEW APPROACH FOR MEASURING SMALL-SCALE FLOW STRUCTURES , 1999 .

[7]  R. Miles,et al.  Velocity measurements by vibrational tagging and fluorescent probing of oxygen. , 1987, Optics letters.

[8]  U. Frisch,et al.  Transverse velocity increments in turbulent flow using the RELIEF technique , 1997, Journal of Fluid Mechanics.

[9]  H. Spiecker,et al.  The photodissociation of tert-butyl nitrite at 193 nm , 1999 .

[10]  P. Brimblecombe,et al.  Chemistry of Atmospheres. , 1986 .

[11]  Paul H. Krupenie.  The Spectrum of Molecular Oxygen , 1972 .

[12]  J. W. Winchester,et al.  Chemistry of atmospheres, 2nd ed.: Edited by Richard P. Wayne. Oxford University Press, 1991, US $85.00 (cloth; ISBN 0-19-855574-1), US $39.95 (paper, ISBN 0-19-855571-7) , 1993 .

[13]  R. Hanson,et al.  Velocity visualization in gas flows using laser-induced phosphorescence of biacetyl , 1984 .

[14]  H. Rubinsztein-Dunlop,et al.  Supersonic velocimetry in a shock tube using laser enhanced ionisation and planar laser induced fluorescence , 1997 .