Vortex suppression and drag reduction in the wake of counter-rotating cylinders

Andre S. Chan, Peter A. Dewey, Antony Jameson, Chunlei Liang, Alexander J. Smits

Research output: Contribution to journalArticlepeer-review

59 Scopus citations

Abstract

The flow over a pair of counter-rotating cylinders is investigated numerically and experimentally. It is demonstrated that it is possible to suppress unsteady vortex shedding for gap sizes from one to five cylinder diameters, at Reynolds numbers from 100 to 200, expanding on the more limited work by Chan & Jameson (Intl J. Numer. Meth. Fluids, vol. 63, 2010, p. 22). The degree of unsteady wake suppression is proportional to the speed and the direction of rotation, and there is a critical rotation rate where a complete suppression of flow unsteadiness can be achieved. In the doublet-like configuration at higher rotational speeds, a virtual elliptic body that resembles a potential doublet is formed, and the drag is reduced to zero. The shape of the elliptic body primarily depends on the gap between the two cylinders and the speed of rotation. Prior to the formation of the elliptic body, a second instability region is observed, similar to that seen in studies of single rotating cylinders. It is also shown that the unsteady wake suppression can be achieved by rotating each cylinder in the opposite direction, that is, in a reverse doublet-like configuration. This tends to minimize the wake interaction of the cylinder pair and the second instability does not make an appearance over the range of speeds investigated here.

Original languageEnglish (US)
Pages (from-to)343-382
Number of pages40
JournalJournal of Fluid Mechanics
Volume679
DOIs
StatePublished - Jul 25 2011

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Keywords

  • drag reduction
  • instability control
  • vortex interactions

Fingerprint Dive into the research topics of 'Vortex suppression and drag reduction in the wake of counter-rotating cylinders'. Together they form a unique fingerprint.

Cite this