The research efforts carried out at ARAP during the past five years in the field of viscous vortex motions are summarized. The work cited constitutes a rather extensive program of theo retical and experimental studies of vortex mo tions in general and of three-dimensional laminar and turbulent incompressible driven vortices in particular. The theoretical studies fall into three general categories; the first and most important comprising velocity distributions for steady laminar motion, the second dealing with unsteady velocity characteristics, and the third treating temperature distributions for the steady motions first considered. An evaluation and discussion of the effects of turbulence in real flows of the general type under consideration is included. The work performed and the results and conclusions reached in each of the areas of study already mentioned are discussed. (Author).

An experimental and computational study of the impact of a vortex with a body oriented normal to the vortex axis was performed. Particular focus was placed on understanding characteristics of the secondary vorticity ejected from the body and the interaction of the secondary vorticity with the primary vortex. Since both onset of boundary layer separation and the form of the secondary vorticity structures are sensitive to variation of the velocity normal to the body axis, the effect of normal velocity on vortex-body interaction was carefully examined. The physical features of the flow evolution were categorized in terms of an impact parameter and a thickness parameter, which respectively represent ratios of velocity and length scales associated with the vortex to those associated with the flow in the absence of the vortex. Experiments were performed using a combination of laser-induced fluorescence (LIF) flow visualization and particle-image velocimetry (PIV) in a water tank to examine the form of the secondary vorticity structures with both "high" and "low" values of the impact parameter for normal vortex interaction with a circular cylinder and with a thin blade. A new type of Lagrangian vorticity method based on a tetrahedral mesh was developed and applied to compute the secondary vorticity evolution during vortex-cylinder interaction. Computations were also performed for model problems to examine in detail wrapping of a vortex loop around a columnar vortex and impulsive cutting of a columnar vortex with finite axial flow.