• Title, Summary, Keyword: wind engineering

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Non-stationary and non-Gaussian characteristics of wind speeds

  • Hui, Yi;Li, Bo;Kawai, Hiromasa;Yang, Qingshan
    • Wind and Structures
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    • v.24 no.1
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    • pp.59-78
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    • 2017
  • Non-stationarity and non-Gaussian property are two of the most important characteristics of wind. These two features are studied in this study based on wind speed records measured at different heights from a 325 m high meteorological tower during the synoptic wind storms. By using the time-frequency analysis tools, it is found that after removing the low frequency trend of the longitudinal wind, the retained fluctuating wind speeds remain to be asymmetrically non-Gaussian distributed. Results show that such non-Gaussianity is due to the weak-stationarity of the detrended fluctuating wind speed. The low frequency components of the fluctuating wind speeds mainly contribute to the non-zero skewness, while distribution of the high frequency component is found to have high kurtosis values. By further studying the decomposed wind speed, the mechanisms of the non-Gaussian distribution are examined from the phase, turbulence energy point of view.

Wind tunnel study of wind structure at a mountainous bridge location

  • Yan, Lei;Guo, Zhen S.;Zhu, Le D.;Flay, Richard G.J.
    • Wind and Structures
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    • v.23 no.3
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    • pp.191-209
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    • 2016
  • Wind tunnel tests of a 1/2200-scale mountainous terrain model have been carried out to investigate local wind characteristics at a bridge location in southeast Tibet, China. Flows at five key locations on the bridge at deck level were measured for 26 directions. It was observed that wind characteristics (including mean wind velocity and overall turbulence intensity) vary significantly depending on the approaching wind direction and measurement position. The wind inclination angle measured in the study fluctuated between $-18^{\circ}$ and $+16^{\circ}$ and the ratio of mean wind velocity to reference wind velocity was small when the wind inclination angles were large, especially for positive wind inclination angles. The design standard wind speed and the minimum critical wind speed for flutter rely on the wind inclination angle and should be determined from the results of such tests. The variation of wind speed with wind inclination angles should be of the asymmetry step type. The turbulence characteristics of the wind were found to be similar to real atmospheric flows.

Fluctuating wind field analysis based on random Fourier spectrum for wind induced response of high-rise structures

  • Lin, Li;Ang, A.H.S.;Xia, Dan-dan;Hu, Hai-tao;Wang, Huai-feng;He, Fu-qiang
    • Structural Engineering and Mechanics
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    • v.63 no.6
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    • pp.837-846
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    • 2017
  • An accurate calculation of the stochastic wind field is the foundation for analyzing wind-induced structure response and reliability. In this research, the spatial correlation of structural wind field was considered based on the time domain method. A method for calculating the stochastic wind field based on cross stochastic Fourier spectrum was proposed. A flowchart of the proposed methodology is also presented in this study to represent the algorithm and workflow. Along with the analysis of regional wind speed distribution, the wind speed time history sample was calculated, and the efficiency can therefore be verified. Results show that the proposed method and programs could provide an efficient simulation for the wind-induced structure response analysis, and help determine the related parameters easily.

Natural wind impact analysis of transiting test method to measure wind pressure coefficients

  • Liu, Lulu;Li, Shengli;Guo, Pan;Wang, Xidong
    • Wind and Structures
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    • v.30 no.2
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    • pp.199-210
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    • 2020
  • Building wind pressure coefficient transiting test is a new method to test the building wind pressure coefficient by using the wind generated by a moving vehicle, which is susceptible to natural wind and other factors. In this paper, the Commonwealth Advisory Aeronautical Research Council standard model with a scale ratio of 1:300 is used as the test object, and the wind pressure coefficient transiting test is repeated under different natural wind conditions to study the influence of natural wind. Natural wind is measured by an ultrasonic anemometer at a fixed location. All building wind pressure coefficient transiting tests meet the test conditions, and the vehicle's driving speed is 72 km/h. The mean wind pressure coefficient, the fluctuating wind pressure coefficient, and the correlation coefficient of wind pressure are used to describe the influence of natural wind on the building wind pressure coefficient transiting test qualitatively and quantitatively. Some rules, which can also help subsequent transiting tests, are also summarized.

A numerical simulation of flow field in a wind farm on complex terrain

  • Lee, Myungsung;Lee, Seung Ho;Hur, Nahmkeon;Choi, Chang-Koon
    • Wind and Structures
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    • v.13 no.4
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    • pp.375-383
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    • 2010
  • A three-dimensional flow simulation was performed to investigate the wind flow around wind-power generation facilities on mountainous area of complex terrain. A digital map of eastern mountainous area of Korea including a wind farm was used to model actual complex terrain. Rotating wind turbines in the wind farm were also modeled in the computational domain with detailed geometry of blade by using the frozen rotor method. Wind direction and speed to be used as a boundary condition were taken from local meteorological reports. The numerical results showed not only details of flow distribution in the wind farm but also the variation in the performance of the wind turbines due to the installed location of the turbines on complex terrain. The wake effect of the upstream turbine on the performance of the downstream one was also examined. The methodology presented in this study may be used in selecting future wind farm site and wind turbine locations in the selected site for possible maximum power generation.

A remote long-term and high-frequency wind measurement system: design, comparison and field testing

  • Zhao, Ning;Huang, Guoqing;Liu, Ruili;Peng, Liuliu
    • Wind and Structures
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    • v.31 no.1
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    • pp.21-29
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    • 2020
  • The wind field measurement of severe winds such as hurricanes (or typhoons), thunderstorm downbursts and other gales is important issue in wind engineering community, both for the construction and health monitoring of the wind-sensitive structures. Although several wireless data transmission systems have been available for the wind field measurement, most of them are not specially designed for the wind data measurement in structural wind engineering. Therefore, the field collection is still dominant in the field of structural wind engineering at present, especially for the measurement of the long-term and high-frequency wind speed data. In this study, for remote wind field measurement, a novel wireless long-term and high-frequency wind data acquisition system with the functions such as remote control and data compression is developed. The system structure and the collector are firstly presented. Subsequently, main functions of the collector are introduced. Also novel functions of the system and the comparison with existing systems are presented. Furthermore, the performance of this system is evaluated. In addition to as the wireless transmission for wind data and hardware integration for the collector, the developed system possesses a few novel features, such as the modification of wind data collection parameters by the remote control, the remarkable data compression before the data wireless transmission and monitoring the data collection by the cell phone application. It can be expected that this system would have wide applications in wind, meteorological and other communities.

Smooth Wind Power Fluctuation Based on Battery Energy Storage System for Wind Farm

  • Wei, Zhang;Moon, Byung Young;Joo, Young Hoon
    • Journal of Electrical Engineering and Technology
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    • v.9 no.6
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    • pp.2134-2141
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    • 2014
  • This paper addresses on a wind power system with BESS(Battery Energy Storage System). The concerned system consists of four parts: the wind speed production model, the wind turbine model, configure capacity of the battery energy storage, battery model and control of the BESS. First of all, we produce wind speed by 4-component composite wind speed model. Secondly, the maximum available wind power is determined by analyzing the produced wind speed and the characteristic curve of wind power. Thirdly, we configure capacity of the BESS according to wind speed and characteristic curve of wind speed-power. Then, we propose a control strategy to track the power reference. Finally, some simulations have been demonstrated to visualize the feasibility of the proposed methodology.

Analysis of aerodynamic characteristics of 2 MW horizontal axis large wind turbine

  • Ilhan, Akin;Bilgili, Mehmet;Sahin, Besir
    • Wind and Structures
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    • v.27 no.3
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    • pp.187-197
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    • 2018
  • In this study, aerodynamic characteristics of a horizontal axis wind turbine (HAWT) were evaluated and discussed in terms of measured data in existing onshore wind farm. Five wind turbines (T1, T2, T3, T4 and T5) were selected, and hub-height wind speed, $U_D$, wind turbine power output, P and turbine rotational speed, ${\Omega}$ data measured from these turbines were used for evaluation. In order to obtain characteristics of axial flow induction factor, a, power coefficient, $C_p$, thrust force coefficient, $C_T$, thrust force, T and tangential flow induction factor, a', Blade Element Momentum (BEM) theory was used. According to the results obtained, during a year, probability density of turbines at a rotational speed of 16.1 rpm was determined as approximately 45%. Optimum tip speed ratio was calculated to be 7.12 for most efficient wind turbine. Maximum $C_p$ was found to be 30% corresponding to this tip speed ratio.

Reliability assessment of ERA-Interim/MERRA reanalysis data for the offshore wind resource assessment (해상풍력자원 평가를 위한 ERA-Interim/MERRA 재해석 데이터 신뢰성 평가)

  • Byun, Jong-Ki;Son, Jin-Hyuk;Ko, Kyung-Nam
    • Journal of the Korea Society For Power System Engineering
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    • v.20 no.4
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    • pp.44-51
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    • 2016
  • An investigation on reliability of reanalysis wind data was conducted using the met mast wind data at four coastal regions, Jeju Island. Shinchang, Handong, Udo and Gangjeong sites were chosen for the met mast sites, and ERA-Interim and MERRA reanalysis data at two points on the sea around Jeju Island were analyzed for creating Wind Statistics of WindPRO software. Reliability of reanalysis wind data was assessed by comparing the statistics from the met mast wind data with those from Wind Statistics of WindPRO software. The relative error was calculated for annual average wind speed, wind power density and annual energy production. In addition, Weibull wind speed distribution and monthly energy production were analyzed in detail. As a result, ERA-Interim reanalysis data was more suitable for wind resource assessment than MERRA reanalysis data.

Wind tunnel tests on flow fields of full-scale railway wind barriers

  • Su, Yang;Xiang, Huoyue;Fang, Chen;Wang, Lei;Li, Yongle
    • Wind and Structures
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    • v.24 no.2
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    • pp.171-184
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    • 2017
  • The present study provides a deeper understanding of the flow fields of a full-scale railway wind barriers by means of a wind tunnel test. First, the drag forces of the three wind barriers were measured using a force sensor, and the drag force coefficients were compared with a similar scale model. On this basis, the mean wind velocity and turbulence upwind and downwind of the wind barriers were measured. The effects of pore size and opening forms of the wind barrier were discussed. The results show that the test of the scaled wind barrier model may be unsafe, and it is suitable to adopt the full-scale wind barrier model. The pore size and the opening forms of wind barriers have a slight influence on the flow fields upwind of the wind barrier but have some influences on the flow fields and power spectra downwind of the wind barrier. The smaller pore size generates a lower turbulence density and value of the power spectrum near the wind barrier, and the porous wind barriers clearly provide better shelter than the bar-type wind barriers.