Large-Eddy Simulation of the Gust Index in an Urban Area Using the Lattice Boltzmann Method

Ahmad, Nurul Huda; Inagaki, Atsushi; Kanda, Manabu; Onodera, Naoyuki; Aoki, Takayuki

doi:10.1007/s10546-017-0233-6

Cited by 62 publications

(24 citation statements)

References 34 publications

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“…Through using a massively parallelized supercomputer, the authors simulated the detailed wind field at 1-m resolution over individual buildings in an area of approximately 10 km × 10 km in the city of Tokyo, Japan. Ahmad et al (2017) and Inagaki et al (2017) used the same code to perform simulations of the spatial development of a neutral boundary layer over an actual urban geometry near Tokyo with 2-m resolution in a domain of 19.2 × 4.8 × 1.0 km 3 . The latter simulation allowed the authors to conduct simultaneous analysis of the aerodynamic properties both of boundary-layer-scale eddies and of gusty motions in street canyons.…”

Section: Introductionmentioning

confidence: 99%

Large-Eddy Simulation of Neutrally-Stratified Turbulent Flow Within and Above Plant Canopy Using the Central-Moments-Based Lattice Boltzmann Method

Watanabe

Shimoyama

Kawashima

et al. 2020

Boundary-Layer Meteorol

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A central-moments-based lattice Boltzmann model for large-eddy simulation of neutrallystratified turbulent flows is described. Through comparative simulations of the airflow within and above a homogeneous plant canopy, the performance of the model is evaluated with respect to a conventional large-eddy-simulation model based on the incompressible Navier-Stokes equations. Simulated turbulence statistics, such as the mean velocity, velocity variances, velocity skewness, and power spectra, are shown to be almost identical between the two models. The spatial structure of coherent eddies and their maintenance processes are also confirmed to be properly represented by the lattice Boltzmann method through analysis of the turbulence kinetic energy budget and spatial two-point correlation functions. Using the simulated results, the energetics of the streamwise-elongated streaky structures commonly observed over vegetation and urban canopies are examined. While the short-wavelength components of the shear-generated streamwise kinetic energy are redirected rapidly by pressure to the lateral and vertical velocity components, long-wavelength energy tends to remain in the streamwise velocity component, which is dissipated in relatively slower processes. Consequently, the streaky structures persist in the streamwise velocity component.

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Section: Introductionmentioning

confidence: 99%

Large-Eddy Simulation of Neutrally-Stratified Turbulent Flow Within and Above Plant Canopy Using the Central-Moments-Based Lattice Boltzmann Method

Watanabe

Shimoyama

Kawashima

et al. 2020

Boundary-Layer Meteorol

Self Cite

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“…The idea for this normalization was to use the WRF outputs as a reference to obtain quantitative values for wind speeds within urban canopy, as described in Section 3.2. Ahmad et al (2017) demonstrated the usefulness of this normalization to assess gust intensities within urban canopies at different locations.…”

Section: Meteorological Model Settingsmentioning

confidence: 99%

Quantitative Estimation of Strong Winds in an Urban District during Typhoon Jebi (2018) by Merging Mesoscale Meteorological and Large-Eddy Simulations

Takemi

Yoshida

Yamasaki

et al. 2019

SOLA

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An intense tropical cyclone, Typhoon Jebi (2018), landed the central part of Japan and caused severe damages. Quantitative assessment of strong winds in urban districts under typhoon conditions is important to understand the underlying risks. As a preliminary study, we investigate the influences of densely built urban environments on the occurrence of wind gusts in an urban district of Osaka City during Typhoon Jebi by merging mesoscale meteorological and building-resolving large-eddy simulations (LES). With the successful reproduction of the track and intensity of the typhoon in meteorological simulations, the simulated winds at the boundary-layer top of the LES model are used to quantitatively estimate the wind gusts in the urban district. The maximum wind gust in the analysis area of Osaka was estimated as 60− 70 m s −1 , which is comparable to the wind speed at the height of about 300 m.

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“…Ten years later, this approach is receiving more and more interest because of its efficiency, although being still an emergent method. Contemporary studies especially address its accuracy and computational performance when implemented on GPUs (Obrecht et al, 2015;King et al, 2017), take advantage of this massively parallelizable method to discuss the link between urban morphology and pedestrian comfort (Ahmad et al, 2017;, or to quantify uncertainties or assimilate data for pollutant dispersion (Margheri and Sagaut, 2016;Mons et al, 2017).…”

Section: A C C E P T E D Accepted Manuscriptmentioning

confidence: 99%

Lattice-Boltzmann Large-Eddy Simulation of pollutant dispersion in street canyons including tree planting effects

Merlier

Jacob

Sagaut

2018

Atmospheric Environment

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This study assesses the performance of a large eddy simulation (LES) based on the lattice Boltzmann method (LBM) in predicting near field dispersion in street canyons with tree planting. Based on a benchmark test case benefiting from wind tunnel measurements (CODASC), this study qualitatively and quantitatively discusses the prediction of traffic-induced pollutant concentration with respect to several reference studies. It also analyses the physics of the flow and concentration fields. Although the problem might seem rather simple, the flow is highlighted to be strongly three dimensional and transient. These properties enhance pollutant dispersion in the empty street canyon but air flow velocity and turbulence intensity tend to decrease in tree crowns. This effect of trees increases both mean and peak concentration levels at pedestrian level, which may be problematic in cities with dense traffic. These results show that LBM-LES is particularly well suited to study dispersion problems towards the development of more breathable cities.

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Large-Eddy Simulation of the Gust Index in an Urban Area Using the Lattice Boltzmann Method

Cited by 62 publications

References 34 publications

Large-Eddy Simulation of Neutrally-Stratified Turbulent Flow Within and Above Plant Canopy Using the Central-Moments-Based Lattice Boltzmann Method

Large-Eddy Simulation of Neutrally-Stratified Turbulent Flow Within and Above Plant Canopy Using the Central-Moments-Based Lattice Boltzmann Method

Quantitative Estimation of Strong Winds in an Urban District during Typhoon Jebi (2018) by Merging Mesoscale Meteorological and Large-Eddy Simulations

Lattice-Boltzmann Large-Eddy Simulation of pollutant dispersion in street canyons including tree planting effects

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