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Periodic Structures within the Formation Region of Trailing Vortices
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 03, 2006 by SAE International in United States
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Water tow-tank tests were performed for the Ahmed model at a range of “high-drag” backlight angles at Reynolds numbers of up to 1.3 × 105. Dye was injected just upstream of the c-pillars and visualizations were recorded with a submerged CCD camera moving with the model.
Discrete sub-vortices were found to be shed periodically along the length of the c-pillar at Strouhal numbers (based on square root of frontal area) between 8 and 12. These sub-vortices were observed to undergo vortex pairing and then to roll up into the familiar c-pillar vortices. These observations are consistent with previously published observations for delta wings.
Wind tunnel tests were performed in order to provide Reynolds numbers of up to 1.6 × 106. These revealed some spectral features which could be due to the shedding and pairing of discrete vortices from the c-pillar but the evidence was much less conclusive than at low Reynolds number.
CitationSims-Williams, D., Kaye, S., and Watkins, S., "Periodic Structures within the Formation Region of Trailing Vortices," SAE Technical Paper 2006-01-1032, 2006, https://doi.org/10.4271/2006-01-1032.
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