OBLIQUE VORTEX SHEDDING BEHIND TAPERED CYLINDERS

✍ Scribed by B. VALLÈS; H.I. ANDERSSON; C.B. JENSSEN

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 757 KB
• Volume: 16
• Category: Article
• ISSN: 0889-9746
• DOI: 10.1006/jfls.2001.0431

✦ Synopsis

The vortex shedding in the wake behind linearly tapered circular cylinders has been considered for the two taper ratios 75:1 and 100:1. The Reynolds number based on the velocity of the incoming #ow and the largest diameter was in the range from 130 to 180. The low Reynolds number assured that laminar #ow prevailed in the entire #ow "eld. The full unsteady threedimensional Navier}Stokes equations were solved numerically with the view of exploring the rather complex vortex shedding phenomena caused by the variation of the natural shedding frequency along the span of the cylinder. The accurate computer simulations showed that this variation gave rise to discrete shedding cells, each with its own characteristic frequency and inclined with respect to the axis of the cylinder. Flow visualizations revealed that vortex dislocation and splitting took place in the numerically simulated #ow "elds. The computer simulations compared surprisingly well with the extensive laboratory experiments reported by Piccirillo & Van Atta in 1993 for a range of comparable conditions; this has enabled detailed analyses of other #ow variables (notably pressure and vorticity) than those readily accessible in a physical experiment. However, distinct di!erences in the vortex dynamics are observed in some of the cases.