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Low-Reynolds number flow around a square cylinder at incidence: Study of blockage, onset of vortex shedding and outlet boundary condition

Sohankar, Ahmad ; Norberg, Christoffer LU and Davidson, Lars (1998) In International Journal for Numerical Methods in Fluids 26(1). p.39-56
Abstract
Calculations of unsteady 2D flow around a square cylinder at incidence (α=0°−45°) are presented. The Reynolds numbers are low (Re=45–200) so that the flow is presumably laminar. A von Kármán vortex sheet is predicted behind the cylinders with a periodicity which agrees well with experiments. An incompressible SIMPLEC code is used with a non-staggered grid arrangement. A third-order QUICK scheme is used for the convective terms. The time discretization is implicit and a second-order Crank–Nicolson scheme is employed. At the outlet of the computational domain a convective Sommerfeld boundary condition is compared with a traditional Neumann condition. The convective boundary condition is shown to be more effective in reducing the CPU time,... (More)
Calculations of unsteady 2D flow around a square cylinder at incidence (α=0°−45°) are presented. The Reynolds numbers are low (Re=45–200) so that the flow is presumably laminar. A von Kármán vortex sheet is predicted behind the cylinders with a periodicity which agrees well with experiments. An incompressible SIMPLEC code is used with a non-staggered grid arrangement. A third-order QUICK scheme is used for the convective terms. The time discretization is implicit and a second-order Crank–Nicolson scheme is employed. At the outlet of the computational domain a convective Sommerfeld boundary condition is compared with a traditional Neumann condition. The convective boundary condition is shown to be more effective in reducing the CPU time, reducing the upstream influence of the outlet and thus reducing the necessary downstream extent of the domain. A study of the effects of spatial resolution and blockage is also provided. The onset of vortex shedding is investigated by using the Stuart–Landau equation at various angles of incidence and for a solid blockage of 5%. A number of quantities such as Strouhal number and drag, lift and moment coefficients are calculated. (Less)
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author
; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
International Journal for Numerical Methods in Fluids
volume
26
issue
1
pages
39 - 56
publisher
John Wiley & Sons Inc.
external identifiers
  • scopus:0031898658
ISSN
1097-0363
DOI
10.1002/(SICI)1097-0363(19980115)26:1<39::AID-FLD623>3.0.CO;2-P
language
English
LU publication?
yes
id
335437dc-995a-4a75-b204-380309620f4a
date added to LUP
2022-10-13 17:12:02
date last changed
2022-12-01 04:25:06
@article{335437dc-995a-4a75-b204-380309620f4a,
  abstract     = {{Calculations of unsteady 2D flow around a square cylinder at incidence (α=0°−45°) are presented. The Reynolds numbers are low (Re=45–200) so that the flow is presumably laminar. A von Kármán vortex sheet is predicted behind the cylinders with a periodicity which agrees well with experiments. An incompressible SIMPLEC code is used with a non-staggered grid arrangement. A third-order QUICK scheme is used for the convective terms. The time discretization is implicit and a second-order Crank–Nicolson scheme is employed. At the outlet of the computational domain a convective Sommerfeld boundary condition is compared with a traditional Neumann condition. The convective boundary condition is shown to be more effective in reducing the CPU time, reducing the upstream influence of the outlet and thus reducing the necessary downstream extent of the domain. A study of the effects of spatial resolution and blockage is also provided. The onset of vortex shedding is investigated by using the Stuart–Landau equation at various angles of incidence and for a solid blockage of 5%. A number of quantities such as Strouhal number and drag, lift and moment coefficients are calculated.}},
  author       = {{Sohankar, Ahmad and Norberg, Christoffer and Davidson, Lars}},
  issn         = {{1097-0363}},
  language     = {{eng}},
  number       = {{1}},
  pages        = {{39--56}},
  publisher    = {{John Wiley & Sons Inc.}},
  series       = {{International Journal for Numerical Methods in Fluids}},
  title        = {{Low-Reynolds number flow around a square cylinder at incidence: Study of blockage, onset of vortex shedding and outlet boundary condition}},
  url          = {{http://dx.doi.org/10.1002/(SICI)1097-0363(19980115)26:1<39::AID-FLD623>3.0.CO;2-P}},
  doi          = {{10.1002/(SICI)1097-0363(19980115)26:1<39::AID-FLD623>3.0.CO;2-P}},
  volume       = {{26}},
  year         = {{1998}},
}