The finite-length square cylinder near wake

Wang, H. F.; Zhou, Yu

doi:10.1017/s0022112009990693

Cited by 258 publications

(242 citation statements)

References 61 publications

Supporting

Mentioning

206

Contrasting

Order By: Relevance

“…Wang & Zhou (2009) observed also in a two side-byside circular cylinder wake of Re = 450 both anti-and in-phased vortex sheddings at T /d = 3.0.…”

Section: Spectral Signatures Of Vortices and Strouhal Numbersmentioning

confidence: 63%

“…the passage of the gap flow, in view of the role the gap flow could play in the near-wake dynamics (e.g. Xu et al 2003;Alam & Zhou 2007a;Wang & Zhou 2009;Chern et al 2010): one with an unchanged cross-section and the other with a converging and diverging geometry. A comparison between the observations from the two wakes is insightful for the two effects on the wake dynamics.…”

Section: Discussion: Flow Separation and Gap Flow Passage Effectsmentioning

confidence: 99%

See 1 more Smart Citation

The wake of two side-by-side square cylinders

2011

Self Cite

View full text Add to dashboard Cite

Aerodynamic interference between two cylinders involves most of the generic flow features associated with multiple structures, thus providing an excellent model for gaining physical insight into the wake of multiple cylindrical structures. This work aims to provide an experimental systematic study of the flow behind two side-by-side square cylinders. The square cylinder is a representative model for bluff bodies with sharp corners, characterized by a fixed flow separation point, which are distinct from those of continuous curvature with oscillating separation points, typically represented by the circular cylinder. Experiments were performed at a Reynolds number Re of 4.7 × 10 4 and a cylinder centre-to-centre spacing ratio T /d (d is the cylinder height) of 1.02-6.00. The flow was measured using different techniques, including hot wires, load cell, particle imaging velocimetry and laser-induced fluorescence flow visualization. Four distinct flow regimes and their corresponding T /d ranges are identified for the first time on the basis of the flow structure and the Strouhal number. Physical aspects in each regime, such as interference between shear layers, gap flow deflection and changeover, multiple flow modes, entrainment, recirculation bubble, vortex interactions and formation lengths, are investigated in detail and are connected to the characteristics of the time-averaged and fluctuating fluid forces. The flow displays a marked difference in many facets from that behind two side-by-side circular cylinders, which is linked to their distinct flow separation natures. A crucial role played by the gap flow and its passage geometry in contributing to the observed difference is also unveiled.

show abstract

“…Wang & Zhou (2009) observed also in a two side-byside circular cylinder wake of Re = 450 both anti-and in-phased vortex sheddings at T /d = 3.0.…”

Section: Spectral Signatures Of Vortices and Strouhal Numbersmentioning

confidence: 63%

Section: Discussion: Flow Separation and Gap Flow Passage Effectsmentioning

confidence: 99%

The wake of two side-by-side square cylinders

2011

Self Cite

View full text Add to dashboard Cite

show abstract

“…The flow around a wall-mounted cantilevered cylinder is highly three dimensional and characterized by the interactions among spanwise vortices, tip vortices and base vortices [1] [2] . Both the tip and base vortices induce downwash and upwash flow in the near wake, which attenuate the spanwise Karman vortex shedding [2] .…”

Section: Introductionmentioning

confidence: 99%

“…Both the tip and base vortices induce downwash and upwash flow in the near wake, which attenuate the spanwise Karman vortex shedding [2] . A number of investigations suggest that the flow over the free end of a cantilevered cylinder and the flow around its both sides form a connected arch type vortex structure in the near wake [3] [4] .…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, when symmetrical vortex shedding occurs, the fluctuation of lift is considerably suppressed and has no obvious periodicity. These two states occur randomly in the near wake of a wall-mounted cantilevered cylinder [2] . To reduce the aerodynamic forces and also the flow induced vibration (FIV) of a 2D slander structures, a lot of methods have been investigated.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Free-End Suction Control of the Aerodynamic Forces of a Cantilevered Square Cylinder

Peng¹,

Wang²,

Li³

2017

dtetr

View full text Add to dashboard Cite

Steady slot suction is applied near the leading edge of the free end of a cantilevered square cylinder to investigate its effects on the aerodynamic forces. The slot suction significantly changes the flow separation on the free end and also the aerodynamic forces on the entire cylinder span. The best control result appears at the suction coefficient Q = 1 (Q = U s /U ∞ , where U s is the suction velocity at the slot, and U ∞ is the oncoming flow velocity), with the fluctuation drag and lift reduced by 17.8% and 45.5%, respectively. At Q = 1, the shear flow at the leading edge is weakened and reattaches on the cylinder free end, which results in stronger momentum transport between the free-end shear flow and the wake, thus suppressing the vortex shedding and aerodynamic forces efficiently.

show abstract

Large‐eddy simulation of vortex streets and pollutant dispersion behind high‐rise buildings

Han

Park

Baik

et al. 2017

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

Understanding turbulent flow and pollutant dispersion in urban areas is one of the important problems in urban meteorology and environmental fluid mechanics. In this study, we examine turbulent flow and pollutant dispersion in a densely built‐up area in Seoul, South Korea, using the parallelized large‐eddy simulation model (PALM). In particular, we focus on vortex streets and associated pollutant dispersion behind high‐rise buildings. The turbulence recycling method is used to produce inflow profiles. Vortices are generated near the high‐rise buildings and propagate downstream forming vortex streets behind the high‐rise buildings. To investigate characteristics of the vortex streets, spectral and correlation analyses are performed. The spectral analysis reveals that vortices have a non‐dimensional vortex shedding frequency of 0.1–0.2, and this periodicity is weakened due to the influence of other buildings. The correlation analysis shows that vortices appear frequently in regions of negative pressure perturbation. The vertical turbulent momentum fluxes induced by ejections and sweeps largely contribute to the total vertical turbulent momentum flux downstream of the high‐rise buildings. Especially, ejections in the wake region are stronger compared to other regions because ejections are induced by vortices near the top of the high‐rise buildings. It is found that pollutant dispersion is interrupted by both low‐rise and high‐rise buildings. Strong updraughts behind the high‐rise buildings transport pollutant upward and increase the mean pollutant concentration at upper levels. Vortices forming the vortex streets play a role in pollutant mixing in such a way that the vortices eject air of high pollutant concentration from the wake region behind the high‐rise buildings and entrain air of low pollutant concentration into the wake region. The mixing by vortices is verified by the correlation between vorticity and pollutant concentration.

show abstract

The finite-length square cylinder near wake

Cited by 258 publications

References 61 publications

The wake of two side-by-side square cylinders

The wake of two side-by-side square cylinders

Free-End Suction Control of the Aerodynamic Forces of a Cantilevered Square Cylinder

Large‐eddy simulation of vortex streets and pollutant dispersion behind high‐rise buildings

Contact Info

Product

Resources

About