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Characterization Progress of an Absorption Laser Differential InterferometerAn absorption laser differential interferometer (A-LDI) system can be used to provide simultaneous, colinear measurements of flow properties (pressure, temperature, concentration, velocity) and flow fluctuations. Further characterization work on the absorption aspect of the system is provided in this paper, including characterization of the laser operating parameters, comparisons of two etalons of different free spectral range, and the further evaluation of a fixed-wavelength absorption measurement that can be used to obtain absorption and LDI measurements with the same sampling rate. A 0.4 GHz etalon was demonstrated to provide sufficient fringe peaks at low modulation depths to be used for the low-pressure testing characteristic of hypersonic wind tunnel facilities. The use of a 3 GHz etalon as a low-cost relative wavemeter was tested and validated. Data taken with the fixed-wavelength strategy in a sub-atmospheric test cell using 100% O2was successful and will allow absorption and LDI data to be acquired simultaneously, colinearly, and at the same sampling rate, yielding a truly simultaneous measurement of the flow density fluctuations and the flow mean density.
Document ID
20230017679
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Joshua M Weisberger
(Langley Research Center Hampton, United States)
Brett F Bathel
(Langley Research Center Hampton, United States)
Gregory C Herring
(Langley Research Center Hampton, United States)
Date Acquired
December 5, 2023
Subject Category
Instrumentation and Photography
Meeting Information
Meeting: AIAA SciTech Forum
Location: Orlando, FL
Country: US
Start Date: January 8, 2024
End Date: January 12, 2024
Sponsors: American Institute of Aeronautics and Astronautics
Funding Number(s)
WBS: 109492.02.07.05.06
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
Technical Review
NASA Technical Management
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