Stereoscopic photography of shear flow turbulence

A three-dimensional photographic technique that would be compatible with existing flow facilities, and serviceable in obtaining qualitative information about the nature of the coherent structures in turbulent shear flow is discussed. The three-dimensional technique provides a convected view (moving with the flow) so that the evolution of the structured regions as they develop can be followed. A review of three-dimensional photographic methods including holography, a multicolor filter technique, and stereography is presented. Stereoscopic photography is concluded to be the most viable technique with stereo movies to be of use if reference planes can be provided and the process of locating conjugate points is automated. Details of the photographic equipment and the procedures used are included.