Double-pulse one-dimensional Raman and Rayleigh measurements for the detection of temporal and spatial structures in a turbulent H-2-air diffusion flame

A novel spectroscopic technique for the observation of the temporal development of small spatial structures of temperature and major-species mole fractions in turbulent flames has been developed. It uses two independent lasers and linewise, single-pulse detection systems for Raman-Rayleigh-scattered light. With this technique, all major-species concentrations, temperature, and positions of vortices and flame fronts, combined with scalar dissipation in two directions or heat release, can be measured, for the first time to our knowledge, as a result of one pair of laser pulses separated either in space or time. This yields, to our knowledge, the highest number of correlated quantities that have been obtained in probing turbulent flames of simple chemistry. (C) 1996 Optical Society of America.