Vortex shedding from a row of square bars

Jiro Mizushima, Takeshi Akinaga

Research output: Contribution to journalArticle

Abstract

Interactions of wakes in a flow past a row of square bars, which is placed across a uniform flow, are investigated by numerical simulations and experiments on the tassumption that the flow is two-dimensional and incompressible. At small Reynolds numbers the flow is steady and symmetric with respect not only to streamwise lines through the center of each square bar but also to streamwise centerlines between adjacent square bars. However, the steady symmetric flow becomes unstable at larger Reynolds numbers and make a transition to a steady asymmetric flow with respect to the centerlines between adjacent square bars in some cases or to an oscillatory flow in other cases. It is found that vortices are shed synchronously from adjacent square bars in the same phase or in anti-phase depending upon the distance between the bars when the flow is oscillatory. The origin of the transition to the steady asymmetric flow is identified as a pitchfork bifurcation, while the oscillatory flows with synchronous shedding of vortices are clarified to originate from a Hopf bifurcation. The critical Reynolds numbers of the transitions are evaluated numerically and the bifurcation diagram of the flow is obtained.
Original languageEnglish
Pages (from-to)179-191
Number of pages13
JournalFluid Dynamics Research
Volume32
Issue number4
DOIs
Publication statusPublished - Apr 2003

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vortex shedding
Vortex shedding
steady flow
Reynolds number
Steady flow
Vortex flow
vortices
uniform flow
two dimensional flow
Hopf bifurcation
wakes
diagrams
Computer simulation
simulation
Experiments
interactions

Keywords

  • Reynolds numbers
  • rows of square bars
  • two-dimensional
  • fluid mechanics
  • sychronous shedding of vortices
  • transition
  • bifurcation

Cite this

Mizushima, Jiro ; Akinaga, Takeshi. / Vortex shedding from a row of square bars. In: Fluid Dynamics Research. 2003 ; Vol. 32, No. 4. pp. 179-191.
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Vortex shedding from a row of square bars. / Mizushima, Jiro; Akinaga, Takeshi.

In: Fluid Dynamics Research, Vol. 32, No. 4, 04.2003, p. 179-191.

Research output: Contribution to journalArticle

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AU - Akinaga, Takeshi

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N2 - Interactions of wakes in a flow past a row of square bars, which is placed across a uniform flow, are investigated by numerical simulations and experiments on the tassumption that the flow is two-dimensional and incompressible. At small Reynolds numbers the flow is steady and symmetric with respect not only to streamwise lines through the center of each square bar but also to streamwise centerlines between adjacent square bars. However, the steady symmetric flow becomes unstable at larger Reynolds numbers and make a transition to a steady asymmetric flow with respect to the centerlines between adjacent square bars in some cases or to an oscillatory flow in other cases. It is found that vortices are shed synchronously from adjacent square bars in the same phase or in anti-phase depending upon the distance between the bars when the flow is oscillatory. The origin of the transition to the steady asymmetric flow is identified as a pitchfork bifurcation, while the oscillatory flows with synchronous shedding of vortices are clarified to originate from a Hopf bifurcation. The critical Reynolds numbers of the transitions are evaluated numerically and the bifurcation diagram of the flow is obtained.

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