Molecular Tagging Velocimetry Measurements in Supersonic Micro Jets

2001 ◽  
Author(s):  
Walter R. Lempert ◽  
Naibo Jiang ◽  
Subin Sethuram ◽  
Mo Samimy
Keyword(s):  
Pressure Range ◽  
Static Pressure ◽  
Statistical Uncertainty ◽  
Spectral Emission ◽  
Free Jets ◽  
Light Emitting ◽  
Molecular Tagging Velocimetry ◽  
Molecular Tagging ◽  
Ch Radical ◽  
Emitting Species

Abstract Acetone-based Molecular Tagging Velocimetry (MTV) is demonstrated in high sub-sonic and supersonic (Mach 1.8) nitrogen and air free jets produced by nozzles with exit dimensions of order 1 mm. Measurements are performed in the static pressure range 1–110 torr, with spatial resolution of approximately 10 microns. The statistical uncertainty (2σ) in velocity is found to be of order 6–10 m/sec, approximately independent of flow field pressure. Spectral emission scans indicate that under some circumstances, the CH radical is formed in the flow, which is believed to be the primary light emitting species in air flows.

scholarly journals Photoisomeric molecular tagging velocimetry with CCVJ

2021 ◽  
Vol 6 (4) ◽  
Author(s):  
Markus J. Schmidt ◽  
Benno Käslin ◽  
Thomas Rösgen
Keyword(s):  
Molecular Tagging Velocimetry ◽  
Molecular Tagging

Quantitative NO2 molecular tagging velocimetry at 500 kHz frame rate

2010 ◽  
Vol 97 (22) ◽  
pp. 221103 ◽  
Author(s):  
Naibo Jiang ◽  
Munetake Nishihara ◽  
Walter R. Lempert
Keyword(s):  
Frame Rate ◽  
Molecular Tagging Velocimetry ◽  
Molecular Tagging

Kinetics of NO Tag Formation in Air for Unseeded Molecular Tagging Velocimetry

2004 ◽  
Author(s):  
Sastri Nandula ◽  
Robert Pitz ◽  
Jeroen Bominaar ◽  
Coralie Schoemaecker ◽  
Nico Dam ◽  
...  
Keyword(s):  
Molecular Tagging Velocimetry ◽  
Molecular Tagging ◽  
Kinetics Of

An experimental study of underexpanded sonic, coaxial, swirl jets

2004 ◽  
Vol 218 (1) ◽  
pp. 93-103 ◽  
Author(s):  
K-H Lee ◽  
T Setoguchi ◽  
S Matsuo ◽  
H-D Kim
Keyword(s):  
Static Pressure ◽  
Near Field ◽  
Flow Structures ◽  
Experimental Investigations ◽  
Pressure Measurements ◽  
Annular Nozzle ◽  
Free Jets ◽  
Underexpanded Jets ◽  
Secondary Stream ◽  
The Impact

The present study addresses experimental investigations of the near-field flow structures of an underexpanded sonic, dual, coaxial, swirl jet. The swirl stream is discharged from the secondary annular nozzle and the primary inner nozzle provides the underexpanded free jets. The interactions between the secondary swirl and primary underexpanded jets are quantified by a fine pitot impact and static pressure measurements and are visualized using a shadowgraph optical method. The pressure ratios of the secondary swirl and primary underexpanded jets are varied below 7.0. Experiments are conducted to investigate the effects of the secondary swirl stream on the primary underexpanded jets, compared with the secondary stream of no swirl. The results show that the presence of an annular swirl stream causes the Mach disc to move further downstream, with an increased diameter, and remarkably reduces the fluctuations of the impact pressures in the underexpanded sonic dual coaxial jet, compared with the case of the secondary annular stream with no swirl.

FLEET Velocimetry for Aerodynamics

2022 ◽  
Vol 54 (1) ◽  
pp. 525-553
Author(s):  
Paul M. Danehy ◽  
Ross A. Burns ◽  
Daniel T. Reese ◽  
Jonathan E. Retter ◽  
Sean P. Kearney
Keyword(s):  
High Speed ◽  
Gaseous Medium ◽  
Local Heating ◽  
Molecular Tagging Velocimetry ◽  
Molecular Tagging ◽  
Acoustic Disturbances ◽  
Laser Spark ◽  
Ground Test ◽  
Test Flow ◽  
Selection Of

Long-lasting emission from femtosecond excitation of nitrogen-based flows shows promise as a useful mechanism for a molecular tagging velocimetry instrument. The technique, known as femtosecond laser electronic excitation tagging (FLEET), was invented at Princeton a decade ago and has quickly been adopted and used in a variety of high-speed ground test flow facilities. The short temporal scales offered by femtosecond amplifiers permit nonresonant multiphoton excitation, dissociation, and weak ionization of a gaseous medium near the beam's focus without the generation of a laser spark observed with nanosecond systems. Gated, intensified imaging of the resulting emission enables the tracking of tagged molecules, thereby measuring one to three components of velocity. Effects of local heating and acoustic disturbances can be mitigated with the selection of a shorter-wavelength excitation source. This review surveys the development of FLEET over the decade since its inception, as it has been implemented in several test facilities to make accurate, precise, and seedless velocimetry measurements for studying complex high-speed flows.

Molecular tagging velocimetry and other novel applications of a new phosphorescent supramolecule

1997 ◽  
Vol 23 (5) ◽  
pp. 361-372 ◽  
Author(s):  
C. P. Gendrich ◽  
M. M. Koochesfahani ◽  
D. G. Nocera
Keyword(s):  
Molecular Tagging Velocimetry ◽  
Molecular Tagging ◽  
Novel Applications
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