Journal ArticleDOI
Transient Grating Spectroscopy in a Hot Turbulent Compressible Free Jet
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TLDR
In this paper, the authors measured the speed of an unseeded hot, supersonic, axisymmetric free air jet at atmospheric pressure with 2% uncertainty using laser-induced electrostrictive gratings.Abstract:
Speed of sound profiles of an unseeded hot, supersonic, axisymmetric free air jet at atmospheric pressure are measured with 2% uncertainty using laser-induced electrostrictive gratings. Signal level and lifetime decay with increasing temperature, and no data are obtained for static temperatures above 540 K. The influence of temperature, turbulence, beam steering, and mechanical vibrations on the signal amplitude and lifetime is examined quantitatively. It is argued that electrostrictive gratings are applicable for thermometry and velocimetry in supersonic combustors by employing a powerful pulsed infrared probe beam. The significantly larger beam power raises the signal level by three orders of magnitude, whereas the longer wavelength reduces the effects of beam steering by increasing the angular separation between probe and signal beam.read more
Citations
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Journal ArticleDOI
Temperature and velocity determination of shock-heated flows with non-resonant heterodyne laser-induced thermal acoustics
TL;DR: In this paper, a non-resonant laser-induced thermal acoustics (LITA) mixing technique was applied to post-shock flows within a shock tube.
Journal ArticleDOI
Validation of laser-induced thermal acoustics for chemically reacting H2/air free jets
TL;DR: In this paper, the authors used a homodyne, resonant LITA setup with a pulsed interrogation beam to investigate a chemically reacting hydrogen/air free jet with a flat flame burner.
Journal ArticleDOI
Measurements of mean and fluctuating temperature in an underexpanded jet using electrostrictive laser-induced gratings
Joel P. Kuehner,F. Andrew Tessier,Allan Kisoma,Jonathan G. Flittner,Michael R. McErlean,Michael R. McErlean +5 more
TL;DR: In this paper, an underexpanded jet was operated at a nozzle pressure ratio of 2.39 and a fully expanded jet Mach number of 1.19 by using electrostrictive laser-induced gratings.
Journal ArticleDOI
Development of Laser-Induced Grating Spectroscopy for Application in Shock Tunnels
TL;DR: In this paper, an optical setup for laser-induced grating spectroscopy is presented, which provides the possibility to induce and analyze electrostrictive gratings as well as thermal gratings.
DissertationDOI
Laser-induced thermal acoustics : simultaneous velocimetry and thermometry for the study of compressible flows
TL;DR: In this article, Kurzzusammenfassassociation is used to evaluate the performance of the Kurzzussammen-fassung approach in the context of online learning.
References
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Approximations for the thermodynamic and transport properties of high-temperature air
TL;DR: In this paper, the authors presented the thermodynamic and transport properties of high-temperature air in closed form starting from approximate partition functions for the major components in air and neglecting all minor components.
MonographDOI
Physical acoustics and metrology of fluids
TL;DR: Physical Acoustics and Metrology of Fluids as mentioned in this paper describes how to design experiments to achieve the highest possible accuracy and how to relate the quantities measured in those experiments to the thermophysical properties of the medium.
Journal ArticleDOI
Laser-induced thermal acoustics (LITA) signals from finite beams.
TL;DR: An analytical expression is derived by the use of linearized equations of hydrodynamics and light scattering that predicts the amplitude and the time history of narrow-band time-resolved LITA and broadband spectrally resolved (mulitplex) L ITA signals.
Journal ArticleDOI
Accuracy limits for planar measurements of flow field velocity, temperature and pressure using Filtered Rayleigh Scattering
TL;DR: In this paper, the authors used filtered Rayleigh scattering to make planar measurements of velocity, temperature and pressure in ambient air and in a Mach 2 free jet, with estimated uncertainties of ±5.4 m/s, ±3.2 K and ±38 torr (±2 to 3, ±2% and ±4-5%, respectively).
Journal ArticleDOI
Temperature measurements in gases using laser-induced electrostrictive gratings
TL;DR: In this paper, the authors used time-resolved light scattering from electrostrictive gratings for the determination of temperatures in gases at atmospheric pressure, where the infrared radiation from a pulsed Nd:YAG laser generates the grating and the beam of a cw laser reads it out.