INTEGRAL LENGTH SCALES IN STRONG WINDS BELOW 20 m

Flay, Richard G.J.; Stevenson, D. C.

doi:10.1016/b978-0-444-87156-5.50010-2

Cited by 12 publications

(14 citation statements)

References 5 publications

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“…Accurate knowledge of the parameter is vital to describe and model the behavior of winds and turbulence in the ABL. There are several methods available to estimate the turbulence integral length scales [31,32]: (1) the turbulence integral length scale can be calculated by the equation…”

Section: Turbulence Integral Length Scalesmentioning

confidence: 99%

Monitoring of typhoon effects on a super-tall building in Hong Kong

Zhi

et al. 2013

Struct. Control Health Monit.

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SUMMARY A super‐tall building with height of 420 m and 88 floors is located in central Hong Kong. Field monitoring of wind effects on the high‐rise structure was conducted during the passage of several typhoons on the basis of a wind and movement monitoring system installed in the building. Field data such as wind speed, wind direction, pressures on cladding, acceleration and displacement responses were simultaneously recorded during the typhoons and then analyzed. Typhoon wind parameters including turbulence intensity, gust factor, peak factor, turbulence integral length scale and power spectral density were presented and discussed. The dynamic properties of the high‐rise structure were determined from the field measurements and compared with those calculated at the design stage. The damping ratios of the super‐tall building were evaluated by a random decrement technique, which demonstrates amplitude‐dependent characteristics. The relationships between the structural dynamic responses and the approaching wind speed were analyzed. Wind tunnel tests were conducted to investigate the wind effects on the super‐tall building. The field‐measured acceleration responses were found to be consistent with the model test results. Finally, the serviceability performance of the super‐tall building during the typhoons was assessed on the basis of the field measurement results. The findings of the paper are expected to be of considerable interest and practical use to professionals and researchers involved in wind‐resistant designs of super‐tall buildings. Copyright © 2013 John Wiley & Sons, Ltd.

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Section: Turbulence Integral Length Scalesmentioning

confidence: 99%

Monitoring of typhoon effects on a super-tall building in Hong Kong

Zhi

et al. 2013

Struct. Control Health Monit.

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“…(7) and they were compared to the ESDU 74031 (1974) data assuming there were no roughness changes upwind of the measuring site. In general, integral length scales in the wind tunnel calculated using autocorrelations functions tend to be slightly larger than the length scales calculated using the peak of the power spectra (Flay andStevenson 1988, Kozmar 2010). The area between the lines represents a range within ±30% tolerance band reported in the ESDU 74031 (1974) for aerodynamic roughness length z 0 = 0.1 m full-scale and z 0 = 0.3 m full-scale.…”

Section: Characteristics Of the Suburban Abl Wind-tunnel Simulationsmentioning

confidence: 99%

Wind-tunnel simulations of the suburban ABL and comparison with international standards

Kozmar¹

2011

Wind and Structures An International Journal

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Abstract. Three wind-tunnel simulations of the atmospheric boundary layer (ABL) flow in suburban country exposure were generated for length scale factors 1:400, 1:250 and 1:220 to investigate scale effects in wind-tunnel simulations of the suburban ABL, to address recommended wind characteristics for suburban exposures reported in international standards, and to test redesigned experimental hardware. Investigated parameters are mean velocity, turbulence intensity, turbulent Reynolds shear stress, integral length scale of turbulence and power spectral density of velocity fluctuations. Experimental results indicate it is possible to reproduce suburban natural winds in the wind tunnel at different length scales without significant influence of the simulation length scale on airflow characteristics. However, in the wind tunnel it was not possible to reproduce two characteristic phenomena observed in full-scale: dependence of integral length scales on reference wind velocity and a linear increase in integral length scales with height. Furthermore, in international standards there is a considerable scatter of recommended values for suburban wind characteristics. In particular, recommended integral length scales in ESDU 85020 (1985) are significantly larger than in other international standards. Truncated vortex generators applied in this study proved to be successful in part-depth suburban ABL wind-tunnel simulation that yield a novel methodology in studies on wind effects on structures and air pollution dispersion.

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“…where U true¯ denotes the mean wind velocity at the measuring point, σ u 2 is the variance of the fluctuating wind velocity, and R u ( τ ) indicates the autocorrelation function of the fluctuating wind velocity of u ( x , t + τ ) and R u ( 0 ) = σ u 2 . Flay and Stevenson (1998) suggested using R u ( τ ) = 0 . 05 σ u 2 as the upper limit of the integral equation.…”

Section: Resultsmentioning

confidence: 99%

Influence of elevated water levels on wind field characteristics at a bridge site

Jing

Liao

et al. 2019

Advances in Structural Engineering

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The influence of elevated water levels on wind field characteristics at bridge sites owing to hydroelectric power stations plays an important role in bridge engineering, particularly in mountainous valley regions. To investigate this issue, a comparative experimental study, which uses a topographic model with two water level states for determining the influence on wind field characteristics at the proposed bridge site located in a mountainous valley area, was conducted in the XNJD-3 wind tunnel at Southwest Jiaotong University, Chengdu, PR China. The altitude difference between the two water level states was approximately 200 m, whereas uniform and D-type boundary layer air inflow conditions were adopted during the wind tunnel test, respectively. The wind speed at the bridge girder and profile of the 1/4, mid, and 3/4 spans were recorded during the experiment. The test results indicated that after the water level was raised, the mean wind speed (or speed-up factor) along the bridge girder decreased by approximately 10%, and the values of the wind profile also decreased. However, the wind profile curve shapes remained approximately unchanged, and the wind attack angle was significantly transformed by approximately 5° in certain locations of the bridge girder. Moreover, the variation in the water level had a negligible influence on the turbulence intensities, turbulence integral length scales, probability distribution of fluctuating wind components, and turbulent wind spectra along the bridge girder. Therefore, as the water level in the canyon rises, the wind field characteristics at the bridge site tend to be conducive to bridge safety. Therefore, long-span bridges located in mountainous valley areas should be designed appropriately according to the expected minimum water level of the river.

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INTEGRAL LENGTH SCALES IN STRONG WINDS BELOW 20 m

Cited by 12 publications

References 5 publications

Monitoring of typhoon effects on a super-tall building in Hong Kong

Monitoring of typhoon effects on a super-tall building in Hong Kong

Wind-tunnel simulations of the suburban ABL and comparison with international standards

Influence of elevated water levels on wind field characteristics at a bridge site

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