Assessing methods to extrapolate the vertical wind-speed profile from surface observations in a city centre during strong winds

Kent, Christoph W.; Grimmond, C. S. B.; Gatey, David; Barlow, Janet F.

doi:10.1016/j.jweia.2017.09.007

Cited by 72 publications

(44 citation statements)

References 74 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results indicate that morphometric methods used to determine z 0 and d that incorporate roughness-element height variability agree better with anemometric methods (Kent et al 2017a). Similar conclusions have been attained from the analysis carried out during strong winds (Kent et al 2018a). The above-mentioned results agree with LES modelling (Kanda et al 2013) that the wind profile is better determined if the maximum height of buildings and the standard deviation of their height are taken into account when determining z 0 and d from city morphometry.…”

Section: Introductionsupporting

confidence: 85%

“…The results of these experiments show that the measured wind speed inside cities is influenced by the height of the anemometer and the distribution of roughness elements around the measurement site. Recently, much information on roughness parameters in cities has been obtained through the analysis of wind-speed measurements at three sites (within 60 m of each other) in London, UK (Kent et al 2017a(Kent et al , 2018a. The results indicate that morphometric methods used to determine z 0 and d that incorporate roughness-element height variability agree better with anemometric methods (Kent et al 2017a).…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

Testing Various Morphometric Methods for Determining the Vertical Profile of Wind Speed Above Krakow, Poland

Godlowska

Kaszowski

2019

Boundary-Layer Meteorol

View full text Add to dashboard Cite

Various morphometric methods used for wind-speed determination in urban areas inside the roughness sublayer have been tested in Krakow, Poland, using a hybrid modelling system. The hybrid modelling system combines the classic numerical meteorological modelling using ALADIN, MM5, and CALMET models with empirical, non-logarithmic relations determined on the basis of a wind-tunnel experiment. In the hybrid modelling system, the horizontally-averaged wind speed is determined using the displacement height d, roughness length z 0 , and an attenuation coefficient α. These parameters are determined using laser scanning data obtained in the MONIT-AIR project. The variability of the selected morphometric parameters in Krakow, the role of the size of the area from which they are determined and the consequences of replacing the frontal area index by the plan area index are analyzed. The different methods used to determine d, z 0, and α are compared and the correctness of the procedures describing the wind profile are verified by comparisons with wind-speed data from road stations, with the wind speed measured between the traffic lanes or at the roadside at a height of 4 m, at standard meteorological stations, and from masts situated on buildings. It is shown that the use of a parametrization based on large-eddy simulations prepared for explicitly resolved buildings in Tokyo and Nagoya in Japan, and taking the maximum instead of the average height of building in empirical relations, significantly improves the modelling results, especially above the average height of buildings.

show abstract

Section: Introductionsupporting

confidence: 85%

Section: Introductionmentioning

confidence: 97%

Testing Various Morphometric Methods for Determining the Vertical Profile of Wind Speed Above Krakow, Poland

Godlowska

Kaszowski

2019

Boundary-Layer Meteorol

View full text Add to dashboard Cite

show abstract

“…The latter two are calculated using the morphometric method by Kanda et al (2013) (subscript 'K') that directly incorporates the roughness-element height variability. The method has been found to provide good estimates compared to other morphometric approaches when assessed with anemometric data (Kent et al 2017(Kent et al , 2018. The parameters in Table 3 are derived for each model area using a 500-m radius (full scale).…”

Section: Morphometric and Roughness Characteristicsmentioning

confidence: 99%

Wake Characteristics of Tall Buildings in a Realistic Urban Canopy

Hertwig

Gough

Grimmond

et al. 2019

Boundary-Layer Meteorol

Self Cite

View full text Add to dashboard Cite

The presence of tall buildings in cities affects momentum and scalar exchange within and above the urban canopy. As wake effects can be important over large distances, they are crucial for urban-flow modelling on and across different spatial scales. We explore the aerodynamic effects of tall buildings on the microscale to local scales with a focus on the interaction between the wake structure, canopy and roughness sublayer flow of the surroundings in a realistic urban setting in central London. Flow experiments in a boundary-layer wind tunnel use a 1:200 scale model with two tall buildings (81 m and 134.3 m) for two wind directions. Large changes in mean flow, turbulence statistics and instantaneous flow structure of the wake are evident when tall buildings are part of the complex urban canopy rather than isolated. In the near-wake, the presence of lower buildings displaces the core of the recirculation zone upwards, thereby reducing the vertical depth over which flow reversal occurs. This amplifies vertical shear at the rooftop and enhances turbulent momentum exchange. In the near part of the main wake, lateral velocity fluctuations and hence turbulence kinetic energy are reduced compared to the isolated building case as eddies generated in the urban canopy and roughness sublayer distribute energy down to smaller scales that dissipate more rapidly. Evaluation of a wake model for flow past isolated buildings suggests model refinements are needed to account for such flow-structure changes in tall-building canopies. Keywords Tall-building environments • Urban canopy • Urban flow • Wake model • Wind tunnel Nomenclature H Building (roof) height H NoTall Mean building height (No Tall) H ave Mean building height Electronic supplementary material The online version of this article (

show abstract

“…By comparing results of Engineering Sciences Data Unit (ESDU) models with LiDAR measurements in strong wind conditions, Drew et al [155] suggested conducting assessments regarding the nature of urban surface when ESDU models are adopted to estimate urban wind profiles, as a result the wind loading on tall buildings can be effectively calculated. In the study of Kent et al [156], wind speeds predicted by a logarithmic model, the Deaves and Harris model, a non-equilibrium model, the power law and the Gryning profile were extrapolated to 200 m above the canopy for comparison with LiDAR observations. When the height variability estimated by morphometric models was taken into consideration, results of the Deaves and Harris model and the Gryning profile showed better agreement with LiDAR measurements compared to all other considered models [156].…”

Section: Urban Meteorologymentioning

confidence: 99%

A Review of Progress and Applications of Pulsed Doppler Wind LiDARs

et al. 2019

Self Cite

View full text Add to dashboard Cite

Doppler wind LiDAR (Light Detection And Ranging) makes use of the principle of optical Doppler shift between the reference and backscattered radiations to measure radial velocities at distances up to several kilometers above the ground. Such instruments promise some advantages, including its large scan volume, movability and provision of 3-dimensional wind measurements, as well as its relatively higher temporal and spatial resolution comparing with other measurement devices. In recent decades, Doppler LiDARs developed by scientific institutes and commercial companies have been well adopted in several real-life applications. Doppler LiDARs are installed in about a dozen airports to study aircraft-induced vortices and detect wind shears. In the wind energy industry, the Doppler LiDAR technique provides a promising alternative to in-situ techniques in wind energy assessment, turbine wake analysis and turbine control. Doppler LiDARs have also been applied in meteorological studies, such as observing boundary layers and tracking tropical cyclones. These applications demonstrate the capability of Doppler LiDARs for measuring backscatter coefficients and wind profiles. In addition, Doppler LiDAR measurements show considerable potential for validating and improving numerical models. It is expected that future development of the Doppler LiDAR technique and data processing algorithms will provide accurate measurements with high spatial and temporal resolutions under different environmental conditions.

show abstract

Assessing methods to extrapolate the vertical wind-speed profile from surface observations in a city centre during strong winds

Cited by 72 publications

References 74 publications

Testing Various Morphometric Methods for Determining the Vertical Profile of Wind Speed Above Krakow, Poland

Testing Various Morphometric Methods for Determining the Vertical Profile of Wind Speed Above Krakow, Poland

Wake Characteristics of Tall Buildings in a Realistic Urban Canopy

A Review of Progress and Applications of Pulsed Doppler Wind LiDARs

Contact Info

Product

Resources

About