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Molecular rayleigh scattering diagnostic for dynamic temperature, velocity, and density measurements
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Mielke, Amy R. Elam, Kristie A. Sung, Chi-Jen |
| Copyright Year | 2006 |
| Description | A molecular Rayleigh scattering technique is developed to measure dynamic gas temperature, velocity, and density in unseeded turbulent flows at sampling rates up to 16 kHz. A high power CW laser beam is focused at a point in an air jet plume and Rayleigh scattered light is collected and spectrally resolved. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. The circular interference fringe pattern is divided into four concentric regions and sampled at 1 and 16 kHz using photon counting electronics. Monitoring the relative change in intensity within each region allows for measurement of gas temperature and velocity. Independently monitoring the total scattered light intensity provides a measure of gas density. A low speed heated jet is used to validate the measurement of temperature fluctuations and an acoustically excited nozzle flow is studied to validate velocity fluctuation measurements. Power spectral density calculations of the property fluctuations, as well as mean and fluctuating quantities are presented. Temperature fluctuation results are compared with constant current anemometry measurements and velocity fluctuation results are compared with constant temperature anemometry measurements at the same locations. |
| File Size | 9618999 |
| Page Count | 16 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20120004153 |
| Archival Resource Key | ark:/13960/t3gx98t8m |
| Language | English |
| Publisher Date | 2006-06-05 |
| Access Restriction | Open |
| Subject Keyword | Optics Rayleigh Scattering Low Speed High Power Lasers Spectra Laser Beams Gas Temperature Plumes Temperature Measurement Diffraction Patterns Sampling Velocity Measurement Fabry-perot Interferometers Continuous Wave Lasers Counting Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
