- Author
-
Pitts, W. M.
|
Kashiwagi, T.
- Title
- Application of Laser-Induced Rayleigh Light Scattering to the Study of Tubulent Mixing.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
- Report
-
NBSIR 83-2641,
February 1983,
114 p.
- Distribution
- Available from National Technical Information Service
- Keywords
-
axisymmetric jets
|
flow fields
|
intermittency
|
lasers
|
ramp-like structures
|
Rayleigh scattering
|
scalars
|
turbulence
|
turbulent flow
- Abstract
- This work describes the development and characterization of an experimental system employing laser-induced Rayeigh light scattering with digital data acquistition as a time-resolved, quantitative concentration probe in the turbulent flow field of a binary gas mixture. Equations for the expected signal and noise levels are given. Estimates of these parameters for the experimental system used here are in satisfactory agreement with experiment. It is demonstrated that the laser Rayleigh light scattering technique provides measurements having high spatial and temporal resolution for various locations within the concentration flow field. Measurements at various position in the flow field of an axisymmetric methane jet issuing into a slow flow of air are reported and, where possible, compared with appropriate literature results. The statistical properties of the turbulent concentration fluctuations are found to be in good agreement with other independent measurements. Conditionally sampled measurements are also reported and shown to behave in the same manner as the limited number of similar measurements in the literature. The capability of caluclating power spectra and correlation functions for the time behavior of the methane concentration is also demonstrated. Other techniques employed for scalar measurements in turbulent flow fields are briefly reviewed and the utility of these techniques for measurements in different types of flow systems are discussed in relation to the Rayleigh light scattering method.