Author(s): Assistant Professor Rupp Carriveau; Professor, Director Gregory A. Kopp; Raouf E. Baddour

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Keywords: Dye-core vortex; Free-surface intake vortex; Intake submergence model; Intake vortex formation; Stretching-sustained vortex; Vortex stretching

Abstract: An experimental investigation of vortices at deep hydraulic intakes revealed two distinct categories of free surface intake vortex. In case 1 when the strain field was strong enough, without an external, quantifiable source of vorticity, minor asymmetries in the near radial intake flow were concentrated and amplified into a vortex core that was purely stretching sustained (PSS). This vortex did not decay so long as the rate of intake withdrawal did not decrease. In case 2, vortex formation required that there be an ample and regular supply of external vorticity to interact with weaker strain fields. These non-purely stretching-sustained (NPSS) vortices decay with a decrease in externally supplied vorticity while maintaining the rate of intake withdrawal. A parameter, here named the stretching-sustained submergence, was postulated to classify conditions suitable for purely stretching sustained vortex formation.

DOI: https://doi.org/10.1080/00221686.2009.9522024

Year: 2009