Optical Apparatus for Turbulence Characterization

An optical technique is proposed for the measurement of turbulence properties in reactive and non-reactive flows. The measurement, averaged along a line of sight, provides information related to the scale of turbulence and the spectral probability distribution function of turbulence energy. The measurement is also sensitive to temperature and composition fluctuations. The technique, based on the propagation of electromagnetic waves through an inhomogeneous medium, fills a gap in the arsenal of non-intrusive diagnostics tools for measurements in flames. The Phase I project objective is to demonstrate and characterize the performance of the technique in the laboratory. In Phase II a measurement system will be built for tests, in the ground-based reduced gravity facilities, in conjunction with a number of the ¿-g combustion experiments being developed by NASA/LeRC. These measurements will provide data currently not available through other means utilized in the laboratory or the ¿-g facilities.