RANS and hybrid LES/RANS simulations of flow over a square cylinder

Ke, Jianghua

doi:10.1186/s42774-019-0012-9

Cited by 14 publications

(6 citation statements)

References 31 publications

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“…RMS pressure coefficients. Similar results were obtained for mean pressures Source: Ke and Yeo (2016).…”

Section: Tornado Hazard Mapping and Tornado-resistant Designsupporting

confidence: 81%

“…Both URANS and IDDES simulations accurately predict the vortex shedding frequency and the velocity field upwind of the wake region. The study (Ke and Yeo 2016) shows that the finest spanwise Figure 8. Contours of the normalized streamwise x-velocity in a vertical yz-cross section.…”

Section: Computational Wind Engineeringmentioning

confidence: 98%

“…URANS and hybrid LES/RANS simulations of flow over a bluff-body. Simulations of flow past a square cylinder were performed by using URANS (Unsteady Reynolds-Average Navier-Stokes) and Hybrid LES/RANS based IDDES (Improved Delayed Detach Eddy Simulation, Shur et al 2008) and the Gieseking blending function (Gieseking et al 2011) simulations to numerically investigate the velocity field around, and pressures distribution and forces over a square cylinder immersed in a uniform, smooth oncoming flow with Reynolds number Re = 21400 (Ke and Yeo 2016). The vortex shedding responses in terms of Strouhal number, the pressure distribution, the velocity profile and the velocity fluctuations obtained by numerical simulations were compared with experimental data (Bearman and Obasaju 1982, Lyn et al 1995, Nishimura and Taniike 2000, Noda and Nakayama 2003.…”

Section: Computational Wind Engineeringmentioning

confidence: 99%

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Recent and Current Wind Engineering Research at the National Institute of Standards and Technology

Duthinh

Levitan

et al. 2018

Wind Engineering for Natural Hazards

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This paper briefly reviews recent and current National Institute of Standards and Technology (NIST) research aimed at improving standard provisions and advancing structural design practice for wind loads. The research covers: (i) New wind speed maps for the conterminous United States; (ii) Risk-consistent estimation of wind load factors for use with the wind tunnel procedure; (iii) Modern peaks-over-threshold approaches to estimation of peak wind effects; (iv) Userfriendly procedures for the database-assisted design of rigid and flexible structures;(v) Novel approaches to codification of pressures on cladding and components; (vi) Modern modeling of synoptic storm planetary boundary layers and its implications for super-tall building design; (vii) Computational Wind Engineering (CWE); (viii) Tornado climatology and development of tornado-resistant design methodologies; (ix) Joint climatology of wind speeds, storm surge and waves heights, and estimates of their combined effects on structures.

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“…RMS pressure coefficients. Similar results were obtained for mean pressures Source: Ke and Yeo (2016).…”

Section: Tornado Hazard Mapping and Tornado-resistant Designsupporting

confidence: 81%

Section: Computational Wind Engineeringmentioning

confidence: 98%

Section: Computational Wind Engineeringmentioning

confidence: 99%

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Recent and Current Wind Engineering Research at the National Institute of Standards and Technology

Duthinh

Levitan

et al. 2018

Wind Engineering for Natural Hazards

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“…This has been observed before, e.g. in the periodic wake of a square cylinder (Ke 2019). A quantitative analysis of the share of periodic and turbulent fluctuations, however, would require time-resolved experimental data (e.g.…”

Section: Time-averaged Velocitymentioning

confidence: 75%

Particle Image Velocimetry Measurements in Accelerated, Transonic Wake Flows

Richter

Alexopoulos

2022

Flow Turbulence Combust

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This paper reports on particle image velocimetry (PIV) measurements in compressible accelerated wake flows generated by two different central injector types, which are mounted in a convergent-divergent nozzle. The injectors differ by the extent of their trailing edge located either in the subsonic (injector A) or supersonic flow region (injector B). In addition, the undisturbed nozzle flow without injector is studied as a reference case. The PIV results reveal typical wake flow structures expected in subsonic (injector A) and supersonic (injector B) wake flows. They further show that the Reynolds stresses $$\mathrm {Re_{xx}}$$ Re xx and $$\mathrm {Re_{yy}}$$ Re yy significantly decay in all three cases due to the strong acceleration throughout the nozzle. Interestingly, in the case of injector A, the flow stays non-isotropic with $$\mathrm {Re_{yy}}>\mathrm {Re_{xx}}$$ Re yy > Re xx also far downstream in the supersonic flow region. These measurements were motivated by the lack of velocity data needed to validate numerical simulations. That is why this paper additionally contains results from (unsteady) Reynolds-averaged Navier-Stokes ((U)RANS) simulations of the two wake flows investigated experimentally. The URANS simulation of the injector A case is able to accurately predict the entire flow field and periodic fluctuations at the wake centerline. However, in the case of injector B, the RANS simulation underestimates the far wake centerline velocity by about $$4\%$$ 4 % .

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“…Fluctuating and time-and phase-averaged characteristics of both the flow structures and their typical length and velocity scales in the base region, as well as in the near and far wake of a sharp-edged square prism in crossflow, were obtained for a wide range of Reynolds numbers by Durao et al (1988) and Lyn et al (1995) using the LDV technique in a water tunnel, by Saha et al (2000), Hacişevki and Teimourian (2015), and Bahrami and Hacişevki (2019) using hot-wire anemometry (HWA), by Hu et al (2006) using particle image velocimetry (PIV) and by Bai and Alam (2018) through measurements using a combination of the last two measurement techniques. Based on the detailed experiments by Durao et al (1988) and Lyn et al (1995), a large amount of research effort has been put into numerical simulations of the small-scale and large-scale flow structures at the specific Reynolds number of Re D = 2.2×10 4 , both by high-order LES approaches (Minguez et al 2011;Cao and Tamura 2016), by direct numerical simulations (DNS) (Saha et al 2001;Trias et al 2015) and by Reynolds-averaged Navier-Stokes simulations (RANS) and hybrid LES/RANS simulations (Ke 2019).…”

Section: Aerodynamics Of Prisms With Square Cross-sectionsmentioning

confidence: 99%

Aerodynamics of smooth and rough square-section prisms at incidence in very high Reynolds-number cross-flows

Hinsberg

2021

Exp Fluids

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The aerodynamics of smooth and slightly rough prisms with square cross-sections and sharp edges is investigated through wind tunnel experiments. Mean and fluctuating forces, the mean pitch moment, Strouhal numbers, the mean surface pressures and the mean wake profiles in the mid-span cross-section of the prism are recorded simultaneously for Reynolds numbers between 1$$\times$$ × 10$$^{5}$$ 5 $$\le$$ ≤ Re$$_{D}$$ D $$\le$$ ≤ 1$$\times$$ × 10$$^{7}$$ 7 . For the smooth prism with $$k_s$$ k s /D = 4$$\times$$ × 10$$^{-5}$$ - 5 , tests were performed at three angles of incidence, i.e. $$\alpha$$ α = 0$$^{\circ }$$ ∘ , −22.5$$^{\circ }$$ ∘ and −45$$^{\circ }$$ ∘ , whereas only both “symmetric” angles were studied for its slightly rough counterpart with $$k_s$$ k s /D = 1$$\times$$ × 10$$^{-3}$$ - 3 . First-time experimental proof is given that, within the accuracy of the data, no significant variation with Reynolds number occurs for all mean and fluctuating aerodynamic coefficients of smooth square prisms up to Reynolds numbers as high as $$\mathcal {O}$$ O (10$$^{7}$$ 7 ). This Reynolds-number independent behaviour applies to the Strouhal number and the wake profile as well. In contrast to what is known from square prisms with rounded edges and circular cylinders, an increase in surface roughness height by a factor 25 on the current sharp-edged square prism does not lead to any notable effects on the surface boundary layer and thus on the prism’s aerodynamics. For both prisms, distinct changes in the aerostatics between the various angles of incidence are seen to take place though. Graphic abstract

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RANS and hybrid LES/RANS simulations of flow over a square cylinder

Cited by 14 publications

References 31 publications

Recent and Current Wind Engineering Research at the National Institute of Standards and Technology

Recent and Current Wind Engineering Research at the National Institute of Standards and Technology

Particle Image Velocimetry Measurements in Accelerated, Transonic Wake Flows

Aerodynamics of smooth and rough square-section prisms at incidence in very high Reynolds-number cross-flows

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