Application of non-Gaussian scattering of laser light to measurements in a propane flame

The photon statistics of light scattered from an expanded laser beam which has passed through a laboratory propane flame are shown to be similar to those for light scattered from other deep random phase screens. The intensity fluctuations arise from the discrete eddy structure of the flame which Schlieren photographs confirm as having a broad size distribution. Intensity cross-correlation measurements using two point detectors positioned in the fluctuating scattered beam and at various distances from the flame give well defined velocities which in the near field are closely related to the convection velocity. It is also shown that when there are clearly defined regions of the flame with different mean convection velocities the cross-correlation measurements give separate results for each region.

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