Effects of organized turbulence structures on the phase distortion in a coherent optical beam propagating through a turbulent shear flow

Effects of organized turbulence structures on the propagation of an optical beam in a turbulent shear flow have been analyzed. An instantaneous passive‐scalar field in a computed homogeneous turbulent shear flow is used to represent index‐of‐refraction fluctuations, and phase distortion induced in a coherent optical beam by turbulent fluctuations is calculated. The organized vortical structures (‘‘hairpin‐shaped’’ eddies) in the turbulent flow give rise to a scalar distribution with elongated regions of intense fluctuation, which have an inclination (about 30°) with respect to the mean flow, similar to that of the characteristic ‘‘hairpin’’ eddies. Two‐point correlations of vorticity and scalar fluctuations support a proposed physical model in which the regions of intense scalar fluctuation are produced primarily by hairpin vortices. It is found that the spatial distribution of the phase distortion has a substantial variation with the direction of propagation. A highly localized distribution of intense ph...

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