Theoretical Experimental Investigation Of Coherent Structure In The Turbulent Boundary Layer

This program combines both experimental flow visualization studies with analytical investigations of a series of phenomenological and theoretical models based upon three-dimensional, vortical flow structures developing and interacting in proximity to a solid surface. The experimental program considered a range of sub-problems including the effect of surface modifications on low-speed streak formation and drag, and the effect of vortex loop inter-action with a solid boundary. To augment visual studies, a computerized interface with the video system has been developed which allows quantitative data to be obtained from flow visualization pictures. The specific thrust of the theoretical studies has been focussed on three areas: (1) how two and three-dimensional vortex structures interact with wall boundary layers; (2) the development of a new type of prediction method for two-dimensional turbulent boundary-layer flows; and (3) improvement in numerical techniques for solving parabolic, boundary-layer equations.