Trailing vortices in stratified fluids
Johnson, S. K.
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Experiments were conducted with two Delta wings and a streamlined body with lifting surfaces to investigate the evolution of turbulent trailing vortices in stratified and unstratified water. The vortex trajectories were determined as a function of the relative depth D/b sub o, normalized time V sub o t/b sub o, and the stratification parameter Nb sub o/V sub o. The results have shown that the vortices rise only to a finite height as they gradually demise under the influence of turbulence, sinusoidal instability, and the vortex breakdown. The effect of stratification is to reduce the lifespan of vortices and the maximum height attained by them. Various approximate analyses have been examined and new ones have been proposed to determine the lifespan of the vortices. Finally, an exploratory numerical analysis of the two-dimensional, unsteady laminar vortices has been carried out with encouraging results. (Author)
NPS Report NumberNPS-69-82-003
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