Analysis of turbulent structures around a rectangular prism building model using spectral proper orthogonal decomposition

Zhang, Bingchao; Ooka, Ryozo; Kikumoto, Hideki

doi:10.1016/j.jweia.2020.104213

Cited by 19 publications

(5 citation statements)

References 25 publications

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“…As shown in Figure 3, the computational domain size is length × width × height = 21b × 13b × 10b. The similar setting has been adopted in previous RANS and LES studies (Liu and Niu 2016;Zhang et al 2020aZhang et al , 2021Ding et al 2022), suggesting that the domain size is sufficient large enough to characterize the mean flow and turbulence around the 2:1 square model. The distances from the building model to the inlet boundary, lateral boundaries, top boundary and outlet boundary are 5b, 6b, 8b and 15b, respectively.…”

Section: Computational Settingsmentioning

confidence: 99%

“…Large eddy simulation (LES) and detached eddy simulation (DES) were also assessed and compared with the wind tunnel measurement (Liu and Niu 2016). In view of the complicated structure of three-dimensional turbulence behind the high-rise building, recent studies advanced statistical technique-spectral proper orthogonal decomposition (SPOD) to elucidate the turbulent structures (Zhang et al 2020a(Zhang et al , 2021. These studies greatly advance our understandings of the flow patterns around the 1:1:2 building.…”

Section: Introductionmentioning

confidence: 99%

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The recirculation flow after different cross-section shaped high-rise buildings with applications to ventilation assessment and drag parameterization

Chen,

Mo,

Hang

2024

Build. Simul.

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The building cross-section shape significantly affects the flow characteristics around buildings, especially the recirculation region behind the high-rise building. Eight generic building shapes including square, triangle, octagon, T-shaped, cross-shaped, #-shaped, H-shaped and L-shaped are examined to elucidate their effects on the flow patterns, recirculation length L and areas A using computational fluid dynamics (CFD) simulations with Reynolds-averaged Navier-Stokes (RANS) approach. The sizes and positions of the vortexes behind the buildings are found to be substantially affected by the building shapes and subsequently changing the recirculation flows. The recirculation length L is in the range of 1.6b -2.6b with an average of 2b. The maximum L is found for L-shaped building (2.6b) while the shortest behind octagon building (1.6b). The vertical recirculation area Av is in the range of 1.5b 2 -3.2b 2 and horizontal area Ah in 0.9b 2 -2.2b 2 . The L, Av and Ah generally increase with increasing approaching frontal area when the wind direction changes but subject to the dent structures of the #-shaped and cross-shaped buildings. The area-averaged wind velocity ratio (AVR), which is proposed to assess the ventilation performance, is in the range of 0.05 and 0.14, which is around a three-fold difference among the different building shapes. The drag coefficient parameterized by Ah varies significantly, suggesting that previous models without accounting for building shape effect could result in large uncertainty in the drag predictions. These findings provide important reference for improving pedestrian wind environment and shed some light on refining the urban canopy parameterization by considering the building shape effect.

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Section: Computational Settingsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The recirculation flow after different cross-section shaped high-rise buildings with applications to ventilation assessment and drag parameterization

Chen,

Mo,

Hang

2024

Build. Simul.

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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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“…The POD method has received historical recognition in fluid dynamics community, in order for representing turbulence data with minimal number of basis functions or modes while preserving as much energy as possible [29][15] [17]. In POD based ROM, a mathematical measure of the reducibility is defined as…”

Section: Flow Past a Cylindermentioning

confidence: 99%

Low-dimensional representation of fluid flows using proper orthogonal decomposition

Alam¹,

Variyath²

2021

Preprint

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The fluid flow around a bluff body is complex and time dependent, which also contains a wide range of time and length scales. The first few eigenmodes of the proper orthogonal decomposition (POD) of such a flow provide significant insight into the flow structure, and can form the basis of a low-dimensional representation of certain turbulent flows. In this article, the direct-forcing immersed boundary method is considered to model the wake flow generated by arbitrary shaped obstacles. Based on the POD analysis of wakes behind cylinders, airfoils, and rotors, a reduced order model (ROM) for the prediction of wake dynamics is studied for arbitrary solid obstacles. For low Reynolds number time periodic flows, the POD based ROM accurately captures the statistically representative coherent motion. For high Reynolds number atmospheric boundary layer flow around rotors, POD provides a low-dimensional representation of the meaningful statistics of coherent motion. The POD based ROM is analyzed for turbulent flow past a rotor in the atmospheric boundary layer, where the flow is not periodic in time.

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Analysis of turbulent structures around a rectangular prism building model using spectral proper orthogonal decomposition

Cited by 19 publications

References 25 publications

The recirculation flow after different cross-section shaped high-rise buildings with applications to ventilation assessment and drag parameterization

The recirculation flow after different cross-section shaped high-rise buildings with applications to ventilation assessment and drag parameterization

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

Low-dimensional representation of fluid flows using proper orthogonal decomposition

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