Interference effects of an adjacent tall building with various sizes on local wind forces acting on a tall building

2017 ◽  
Vol 21 (10) ◽  
pp. 1469-1481 ◽  
Author(s):  
Wonsul Kim ◽  
Yukio Tamura ◽  
Akihito Yoshida ◽  
Jin-Hak Yi
Keyword(s):  
Root Mean Square ◽  
Power Spectra ◽  
Tall Building ◽  
Wind Loads ◽  
Mean Square ◽  
Local Wind ◽  
Wind Tunnel Experiments ◽  
Wind Force ◽  
Adjacent Building ◽  
Critical Locations

This article focuses on variations of local wind forces along height levels of a tall building due to an adjacent tall building with various height and breadth ratios through huge wind tunnel experiments. It deals with the characteristics of local wind forces including root mean square local wind force coefficients, non-dimensional power spectra, and root coherences along height levels of a tall building with an adjacent tall building in critical locations. It is shown that increases of over 20% in interference factors ( MIFMD, RIFMD, and RIFML) for maximum mean and root mean square base overturning moment coefficients in along- and across-wind directions occur when the adjacent building is close to the principal building. Higher and wider adjacent buildings can cause not only higher mean wind loads but also higher dynamic wind loads in along- and across-wind directions, but the critical locations of an adjacent building with various height and breadth ratios are somewhat different. However, most critical locations of an adjacent building for wind-induced wind loads are within the region ( X/ B, Y/ B) = (1.5, 0–1.5).

Adverse Local Wind Loads Induced by Adjacent Building

1983 ◽  
Vol 109 (3) ◽  
pp. 816-820 ◽  
Author(s):  
David Surry ◽  
William Mallais
Keyword(s):  
Wind Loads ◽  
Local Wind ◽  
Adjacent Building

Coherence of Fluctuating Wind Speed and Along-Wind Force Power Spectrum of Tall Building

2014 ◽  
Vol 1025-1026 ◽  
pp. 922-925
Author(s):  
Yong Chul Kim ◽  
Sung Won Yoon
Keyword(s):  
Wind Speed ◽  
Power Spectrum ◽  
Large Scale ◽  
Measurement Data ◽  
Power Spectra ◽  
Tall Building ◽  
Theoretical Formula ◽  
Mathematical Treatment ◽  
Wind Force ◽  
Fluctuating Wind

In evaluating wind load effects on large-scale structures, correlations in the frequency domain (i.e., coherences) and power spectra of fluctuating wind speed should be evaluated in advance. Most existing formulas for coherence are expressed as exponential functions based on field measurement data for ease of mathematical treatment. However, these simple mathematical expressions have many limitations. In the present study, after examining the existing coherence formulas, a semi-theoretical formula was proposed, and the corresponding along-wind force power spectrum of a tall building with a square cross-section was numerically calculated. A comparison showed that both the coherence and along-wind power spectrum were in good agreement with those of actual wind tunnel data.

scholarly journals A minimal time-scale for the spectral states of GX 339−4

2020 ◽  
Vol 499 (2) ◽  
pp. 2513-2522
Author(s):  
E Sonbas ◽  
K Mohamed ◽  
K S Dhuga ◽  
A Tuncer ◽  
E Göğüş
Keyword(s):  
Black Hole ◽  
Root Mean Square ◽  
Time Scale ◽  
Power Spectra ◽  
Mean Square ◽  
X Ray ◽  
Minimal Time ◽  
Power Spectral ◽  
Power Spectral Densities ◽  
Spectral States

ABSTRACT Black hole transients are known to undergo spectral transitions that form q-shaped tracks on a hardness intensity diagram. In this work, we use the archival Rossi X-ray Timing Explorer data to extract a characteristic minimal time-scale for the spectral states in GX 339−4 for the 2002–2003 and 2010 outbursts. We use the extracted time-scale to construct an intensity variability diagram for each outburst. This new diagram is comparable to the traditional hardness intensity diagram and offers the potential for probing the underlying dynamics associated with the evolution of the relevant emission regions in black hole transients. We confirm this possibility by connecting the minimal time-scale with the inner disc radius, Rin (estimated from spectral fits), and demonstrate a positive correlation between these variables as the system evolves through its spectral transitions. Furthermore, we probe the relation between the minimal time-scale and the break frequencies extracted from the power spectral densities. Lastly, we examine a possible link between the extracted time-scale and a traditional measure of variability, i.e. the root mean square, determined directly from the power spectra.

Interference Effect Tall Building to Fluctuations Wind Load

2013 ◽  
Vol 871 ◽  
pp. 9-14
Author(s):  
Ki Pyo You ◽  
Young Moon Kim ◽  
Jang Youl You
Keyword(s):  
Wind Direction ◽  
Interference Effect ◽  
Separation Distance ◽  
Tall Building ◽  
Wind Loads ◽  
Interference Effects ◽  
Existing Building ◽  
Close Vicinity ◽  
Side Ratio ◽  
Adjacent Building

The construction of another tall building in the close vicinity of existing building may lead to a modification in its response. Therefore, the wind loads on buildings in realistic environments may be considerably different from these measured on isolated buildings. Neighboring buildings may either decrease or increase the flow-induced forces on a structure, depending mainly on the geometry and arrangement of these buildings, their orientation with respect to the direction of flow and upstream terrain conditions. In this study deals with mean and fluctuating as well as their spectra on a building due to an adjacent building of side ratio 1 for wind direction from 0 to 45 degree and separation distance between two models. Interference effects were presented in the form of interference factors. And experiments were compared to these measured on isolated building.

Wind Tunnel Test of Symmetrical Twin-Tower Tall Building Model

2014 ◽  
Vol 919-921 ◽  
pp. 518-522
Author(s):  
Jian Guo Zhang ◽  
Hui Min Zhuang
Keyword(s):  
Wind Tunnel ◽  
Root Mean Square ◽  
Wind Direction ◽  
Wind Tunnel Test ◽  
Mean Value ◽  
Tall Building ◽  
Mean Square ◽  
Building Model ◽  
Moment Coefficient ◽  
Peak Value

In this paper, taking symmetrical twin-tower tall building model as an example, a wind tunnel test with simultaneous surface pressure measurement, in 7 wind directions, was carried out. Integration of the surface pressures leads to base moment coefficient, of which the amplitude and frequency-domain characteristics were analyzed and compared with those of single tall building model. The result shows that mean value and root mean square of the interfering tower, in all wind directions, are basically the same as those of single tower, while in 0o wind direction, they differ greatly; mean value and root mean square of the interfered tower differ significantly, in every wind directions, from those of single tower. In 0o wind direction, the reduced spectrum of along-wind and across-wind base moment coefficient is greatly different from that of the single tower; in 90o wind direction, the along-wind base moment coefficient reduced spectrum for interfered tower is different from Davenport spectrum, while the peak value of across-wind base moment coefficient is half the corresponding value of single tower.

The Relationship of Root Mean Square Value of Electromyography and Isometric Torque of Quadriceps in Normal Subjects

2016 ◽  
Vol 26 (1) ◽  
pp. 58
Author(s):  
Qiurong XIE ◽  
Zheng JIANG ◽  
Qinglu LUO ◽  
Jie LIANG ◽  
Xiaoling WANG ◽  
...  
Keyword(s):  
Root Mean Square ◽  
Normal Subjects ◽  
Mean Square ◽  
Isometric Torque ◽  
Relationship Of ◽  
The Relationship

scholarly journals Estimation of Apple Flowering Frost Loss for Fruit Yield Based on Gridded Meteorological and Remote Sensing Data in Luochuan, Shaanxi Province, China

2021 ◽  
Vol 13 (9) ◽  
pp. 1630
Author(s):  
Yaohui Zhu ◽  
Guijun Yang ◽  
Hao Yang ◽  
Fa Zhao ◽  
Shaoyu Han ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Root Mean Square Error ◽  
Mean Square Error ◽  
Root Mean Square ◽  
Minimum Temperature ◽  
Price Regulation ◽  
Flowering Period ◽  
Mean Square ◽  
Prevention Measures ◽  
Agricultural Insurance

With the increase in the frequency of extreme weather events in recent years, apple growing areas in the Loess Plateau frequently encounter frost during flowering. Accurately assessing the frost loss in orchards during the flowering period is of great significance for optimizing disaster prevention measures, market apple price regulation, agricultural insurance, and government subsidy programs. The previous research on orchard frost disasters is mainly focused on early risk warning. Therefore, to effectively quantify orchard frost loss, this paper proposes a frost loss assessment model constructed using meteorological and remote sensing information and applies this model to the regional-scale assessment of orchard fruit loss after frost. As an example, this article examines a frost event that occurred during the apple flowering period in Luochuan County, Northwestern China, on 17 April 2020. A multivariable linear regression (MLR) model was constructed based on the orchard planting years, the number of flowering days, and the chill accumulation before frost, as well as the minimum temperature and daily temperature difference on the day of frost. Then, the model simulation accuracy was verified using the leave-one-out cross-validation (LOOCV) method, and the coefficient of determination (R2), the root mean square error (RMSE), and the normalized root mean square error (NRMSE) were 0.69, 18.76%, and 18.76%, respectively. Additionally, the extended Fourier amplitude sensitivity test (EFAST) method was used for the sensitivity analysis of the model parameters. The results show that the simulated apple orchard fruit number reduction ratio is highly sensitive to the minimum temperature on the day of frost, and the chill accumulation and planting years before the frost, with sensitivity values of ≥0.74, ≥0.25, and ≥0.15, respectively. This research can not only assist governments in optimizing traditional orchard frost prevention measures and market price regulation but can also provide a reference for agricultural insurance companies to formulate plans for compensation after frost.

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