Laser Rayleigh imaging has been applied in a number of flow and flame studies to measure concentration or temperature distributions. Rayleigh cross sections are dependent on the index of refraction of the scattering medium. The same index of refraction changes that provide contrast in Rayleigh images can also deflect the illuminating laser sheet. By applying a ray-tracing algorithm to the detected image, it is possible to correct for some of these beam-steering effects and thereby improve the accuracy of the measured field. Additionally, the quantification of the degree of beam steering through the flow provides information on the degradation of spatial resolution in the measurement. Application of the technique in a well-studied laboratory flame is presented, along with analysis of the effects of image noise and spatial resolution on the effectiveness of the algorithm.
© 2005 Optical Society of America
Original Manuscript: February 2, 2005
Revised Manuscript: May 19, 2005
Manuscript Accepted: May 20, 2005
Published: November 1, 2005
Sebastian A. Kaiser, Jonathan H. Frank, and Marshall B. Long, "Use of Rayleigh imaging and ray tracing to correct for beam-steering effects in turbulent flames," Appl. Opt. 44, 6557-6564 (2005)