Flow field around two tandem non-identical-height square buildings via LES

Freidooni, Farnood; Sohankar, A.; Rastan, M.R.; Shirani, Ebrahim

doi:10.1016/j.buildenv.2021.107985

Cited by 23 publications

(4 citation statements)

References 80 publications

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“…Thanks to the continuous advances in computational power, this review shows that 17.2% of the studies have applied the LES approach to the studies of the PLW flow fields in different urban settings in the recent five years. There are studies focusing on simplified geometries of isolated buildings (Liu, Yu, et al, 2020;Tse et al, 2020;Zhang, Ooka, & Kikumoto, 2020), generic urban settings of building arrays (Freidooni et al, 2021;Ikegaya et al, 2017;Ishida et al, 2018;, street canyons (Duan et al, 2020;Puigferrat et al, 2021;Salim et al, 2020), and complex urban areas (Adamek et al, 2017;Antoniou et al, 2017;Zhang, Kwok, et al, 2021). In some earlier studies, researchers considered different aspects of reality in their simulations.…”

Section: Scale Resolving Simulationsmentioning

confidence: 99%

Recent advances in modeling turbulent wind flow at pedestrian-level in the built environment

Zhong

Liu

Zhao

et al. 2022

ARIN

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Pressing problems in urban ventilation and thermal comfort affecting pedestrians related to current urban development and densification are increasingly dealt with from the perspective of climate change adaptation strategies. In recent research efforts, the prime objective is to accurately assess pedestrian-level wind (PLW) environments by using different simulation approaches that have reasonable computational time. This review aims to provide insights into the most recent PLW studies that use both established and data-driven simulation approaches during the last 5 years, covering 215 articles using computational fluid dynamics (CFD) and typical data-driven models. We observe that steady-state Reynolds-averaged Navier-Stokes (SRANS) simulations are still the most dominantly used approach. Due to the model uncertainty embedded in the SRANS approach, a sensitivity test is recommended as a remedial measure for using SRANS. Another noted thriving trend is conducting unsteady-state simulations using high-efficiency methods. Specifically, both the massively parallelized large-eddy simulation (LES) and hybrid LES-RANS offer high computational efficiency and accuracy. While data-driven models are in general believed to be more computationally efficient in predicting PLW dynamics, they in fact still call for substantial computational resources and efforts if the time for development, training and validation of a data-driven model is taken into account. The synthesized understanding of these modeling approaches is expected to facilitate the choosing of proper simulation approaches for PLW environment studies, to ultimately serving urban planning and building designs with respect to pedestrian comfort and urban ventilation assessment.

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Section: Scale Resolving Simulationsmentioning

confidence: 99%

Recent advances in modeling turbulent wind flow at pedestrian-level in the built environment

Zhong

Liu

Zhao

et al. 2022

ARIN

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“…2019, 2023; Hamed & Peterlein 2020; Freidooni et al. 2021; Essel, Balachandar & Tachie 2023). A salient feature of this configuration is the sheltering of part or the whole span of the DC from direct interaction with the approach flow by the UC (figure 2).…”

Section: Introductionmentioning

confidence: 99%

“…The wake interference of unequal-height tandem FWMCs is more complex than that of identical-height tandem cylinders, yet our understanding is limited to a few previous investigations (Hamed et al 2019(Hamed et al , 2023Hamed & Peterlein 2020;Freidooni et al 2021;Essel, Balachandar & Tachie 2023). A salient feature of this configuration is the sheltering of part or the whole span of the DC from direct interaction with the approach flow by the UC (figure 2).…”

Section: Introductionmentioning

confidence: 99%

Unsteady wake interference of unequal-height tandem cylinders mounted in a turbulent boundary layer

Ouedraogo,

Essel

2023

J. Fluid Mech.

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The unsteady wake interference of unequal-height tandem finite wall-mounted cylinders (FWMCs) fully submerged in a turbulent boundary layer (TBL) was investigated using time-resolved particle image velocimetry. The aspect ratios of the cylinders were fixed at $h/d = 5.3$ for the upstream cylinder (UC) and $H/d = 7.0$ for the downstream cylinder (DC) to achieve a height ratio of $h/H = 0.75$ , where d is the diameter of the cylinders. The Reynolds number based on the cylinder diameter was $Re = 5540$ and the submergence ratio was $\delta /H = 1.2$ , where $\delta $ is the TBL thickness. Three main flow regimes of tandem FWMCs were examined by varying the centre-to-centre spacing ( $s$ ) between the cylinders: extended-body ( $s/d = 2$ ), reattachment ( $s/d = 4$ ) and co-shedding ( $s/d = 6$ ) regimes. These test cases denoted as SR2, SR4 and SR6, respectively, were compared with a reference isolated cylinder (SC) with an aspect ratio similar to that of the DC. Spatio-temporal analysis of the flow field showed that the gap region of SR2 is characterized by a strong downwash of alternating low- and high-momentum fluid induced by the approach flow that is deflected from the unsheltered portion of the DC. In contrast, the gap region of SR4 and SR6 exhibited both downwash and upwash flow with a saddle point that moves closer to the mid-height of the UC as the spacing ratio increases. The upwash and downwash shear layers were associated with small-scale vortices with Strouhal numbers larger than that of the Kármán vortex shedding in the spanwise shear layers. The wake structure behind the DC was significantly altered compared with the SC due to sheltering effects, and the spacing ratio had a significant impact on the spatio-temporal evolution of the vortices.

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“…Comprehensive fundamental knowledge about the effect of the wake downstream triangular cylinder on the other objects may be useful in practice in processes employing BBs to control the flow, especially where the selection of the proper object shape is crucial. Therefore, it is of interest to conduct such a study at least for a very fundamental configuration such as a tandem arrangement [21] where the triangular cylinder would be used as the upstream one and confront the results with classical configuration such as two square cylinders in tandem. The study also included an analysis of the effect of Reynolds number carried out for the subcritical regime.…”

Section: Introductionmentioning

confidence: 99%

Effect of the upstream cylinder shape on the flow around the downstream rectangular object in tandem configuration

Gajewska

Niegodajew

Gnatowska

et al. 2022

J. Phys.: Conf. Ser.

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The paper presents an experimental investigation of air flow around bluff bodies in tandem configurations. The first one concerns two square cylinders and in the second one a triangular cylinder was used as an upstream object. Experiment was performed for two different Reynolds number for the fixed distance between bluff bodies. To have an insight into the fluid flow, particle image velocimetry method was used. Particular attention was paid to examine the effect of the upstream cylinder shape on the flow around the downstream body.

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Flow field around two tandem non-identical-height square buildings via LES

Cited by 23 publications

References 80 publications

Recent advances in modeling turbulent wind flow at pedestrian-level in the built environment

Recent advances in modeling turbulent wind flow at pedestrian-level in the built environment

Unsteady wake interference of unequal-height tandem cylinders mounted in a turbulent boundary layer

Effect of the upstream cylinder shape on the flow around the downstream rectangular object in tandem configuration

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