An optical technique for the direct measurement of the 2-D spectral density of a passive scalar in a turbulent flow
A new optical technique for quantitatively measuring the spectral density of passive scalar fluctuations in a turbulent flow has been developed. The technique exploits the photorefractive properties of BaTiO3 to separate the optical signal of the turbulent field from the coherent illumination background. It is a major improvement over existing techniques in that it is nonintrusive, has excellent spatial resolution, virtually unlimited frequency response, and is capable of simultaneously measuring two components of the three-dimensional spectral density. The technique is thus especially well suited to the direct study of anisotropic flows.
AIAA, Fluid Dynamics, 21st Plasma Dynamics and Lasers Conference, 21st, Seattle, WA, June 18-20, 1990. 17 p.
- Pub Date:
- June 1990
- Anisotropic Fluids;
- Barium Titanates;
- Optical Measuring Instruments;
- Turbulent Flow;
- Channel Flow;
- Frequency Response;
- Heat Transfer;
- Spatial Resolution;
- Instrumentation and Photography