Three-dimensional vortex flow near the endwall of a short cylinder in crossflow: Stepped-diameter circular cylinder

S. B. Chen, S. Sanitjai, K. Ghosh, R. J. Goldstein

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The effect of geometry on the flow around a cylinder in crossflow is investigated in this study. Three different stepped-diameter circular cylinders (SDCC s) with varying step heights are used. Extensive flow visualization using the oil-lampblack and smoke-wire techniques and near wake velocity measurements using a hotwire anemometer reveal complex secondary flows on and around the SDCC. Six vortices are observed in the horseshoe vortex system near the cylinder-endwall junction and six additional vortices are found in the step-induced vortex system on the step surface. Based on these experimental results, new secondary flow models are proposed. The step-induced vortices separate from the step surface at both sides and move toward the endwall, washing down the sides of the top/bottom larger diameter cylinders and interact with the separated shear layer and horseshoe vortices. In this process, they modify the near wake flow significantly: they produce an increase in velocity near the endwall region (below the step) and a decrease in velocity near the mid-span region, even altering the oscillatory behavior of the wake.

Original languageEnglish (US)
Pages (from-to)36-47
Number of pages12
JournalApplied Thermal Engineering
Volume40
DOIs
StatePublished - Jul 1 2012

Keywords

  • Flow visualization
  • Horseshoe vortex
  • Secondary flow
  • Stepped-diameter circular cylinder
  • Uniform-diameter circular cylinder

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