Multi-Parameter Measurement in Unseeded Flows using Femtosecond Lasers

Metadata Updated: February 28, 2019

Our approach is to use new turn-key femtosecond laser technology along with new high-speed CMOS camera technology to build a multi-parameter measurement system based on the Princeton-discovered Femtosecond Laser Electronic Excitation and Tagging (FLEET) technique. Our partners at Princeton and others have recently begun using FLEET to study combustion environments and hypersonic flows. We at NASA realized that FLEET was ideally suited for transonic cryogenic facilities like Langley’s National Transonic Facility (NTF) and we discovered that the signal intensity scales directly with density near atmospheric conditions, meaning that it works even better under cryo conditions than at room temperature. Another innovative aspect has been to use high-speed camera acquisition technology, allowing velocity, acceleration and pathlines to be measured from each laser excitation pulse. We have recently demonstrated such measurements in attached and separated airfoil flows in the Langley 0.3 meter cryo tunnel which is the pilot facility for NTF. One goal for this year is to analyze and evaluate this airfoil data. Another is to improve our ability to measure temperature with the technique, having demonstrated a rudimentary method this past year. Finally we will investigate how well the technique works in supersonic and hypersonic flows this year. Funding from another program (ARMD AETC) is being used to implement optical access into the NTF for future measurements. SBIR funding is supporting our partner company to investigate alternate versions of FLEET called STARFLEET, which uses less energy thereby perturbing the flow less, and PLEET which uses a picosecond laser which can operate at ~100 kHz (about 100x faster than FLEET). After this year we anticipate bringing the FLEET, STARFLEET and PLEET technologies to NTF to study the freestream and also flowfields around vehicles.

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Public: This dataset is intended for public access and use. License: U.S. Government Work

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Metadata Created Date August 1, 2018
Metadata Updated Date February 28, 2019

Metadata Source

Harvested from NASA Data.json

Additional Metadata

Resource Type Dataset
Metadata Created Date August 1, 2018
Metadata Updated Date February 28, 2019
Publisher Space Technology Mission Directorate
Unique Identifier TECHPORT_93859
Maintainer Email
Public Access Level public
Bureau Code 026:00
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Harvest Object Id c0384481-4d72-4230-b664-8ee4f054ea81
Harvest Source Id 39e4ad2a-47ca-4507-8258-852babd0fd99
Harvest Source Title NASA Data.json
Data First Published 2017-07-01
Homepage URL
Data Last Modified 2018-07-19
Program Code 026:027
Source Datajson Identifier True
Source Hash 0a10ee8a3819dc323f7c8c65ac29bea02aee0056
Source Schema Version 1.1

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