COHERENT STRUCTURE EFFECTS ON THE OPTICAL-PERFORMANCE OF PLANE SHEAR LAYERS

Although there has been extensive research on the optical properties of shear layers, there have been no reported studies of the optical effects on large scale coherent structures existing in turbulent shear layers. The research reported here investigated the effects of such coherent structures and of external perturbation of the shear layer on the optical quality of a propagating laser beam. High-speed pictures suggest that the presence of large eddies influences the shape of the far-field intensity profiles. In addition, time-averaged pictures show that perturbing a shear layer can affect the Strehl ratio. These results demonstrate that the optical properties of shear layers may be controlled and improved.