• Wind and Structures
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• v.20 no.5
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• pp.701-718
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• 2015

The joint distribution of wind speed and wind direction at a bridge site is vital to the estimation of the basic wind speed, and hence to the wind-induced vibration analysis of long-span bridges. Instead of the conventional way relying on the weather stations, this study proposed an alternate approach to obtain the original records of wind speed and the corresponding directions based on field measurement supported by the Structural Health Monitoring System (SHMS). Specifically, SHMS of Sutong Cable-stayed Bridge (SCB) is utilized to study the basic wind speed with directional information. Four anemometers are installed in the SHMS of SCB: upstream and downstream of the main deck center, top of the north and south tower respectively. Using the recorded wind data from SHMS, the joint distribution of wind speed and direction is investigated based on statistical methods, and then the basic wind speeds in 10-year and 100-year recurrence intervals at these four key positions are calculated. Analytical results verify the reliability of the recorded wind data from SHMS, and indicate that the joint probability model for the extreme wind speed at SCB site fits well with the Weibull model. It is shown that the calculated basic wind speed is reduced by considering the influence of wind direction. Compared to the design basic wind speed in the Specification of China, basic wind speed considering the influence of direction or not is much smaller, indicating a high safety coefficient in the design of SCB. The results obtained in this study can provide not only references for further wind-resistance research of SCB, but also improve the understanding of the safety coefficient for wind-resistance design of other engineering structures in the similar area.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.2
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• pp.29-40
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• 2018

Strength design wind loads for the wind resistance design of structures shall be evaluated by the product of wind loads calculated based on the basic wind speed with 100 years return period and the wind load factor 1.3 specified in the provisions of load combinations in Korean Building Code (KBC) 2016. It may be sure that the wind load factor 1.3 in KBC(2016) had not been determined by probabilistic method or empirical method using meteorological wind speed data in Korea. In this paper, wind load factors were evaluated by probabilistic method and empirical method. The annual maximum 10 minutes mean wind speed data at 69 meteorological stations during past 40 years from 1973 to 2012 were selected for this evaluation. From the comparison of the results of those two method, it can be found that the mean values of wind load factors calculated both probability based method and empirical based method were similar at all meteorological stations. When target level of reliability index is set up 2.5, the mean value of wind load factors for all regions should be presented about 1.35. When target level of reliability index is set up 3.0, wind load factor should be presented about 1.46. By using the relationship between importance factor(conversion factor for return period) and wind load factor, the return periods for strength design were estimated and expected wind speeds of all regions accounting for strength design were proposed. It can be found that return period to estimate wind loads for strength design should be 500 years and 800 years in according to target level of reliability index 2.5 and 3.0, respectively. The 500 years basic wind speed map for strength design was suggested and it can be used with a wind load factor 1.0.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.188.1-188.1
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• 2010

This paper describes the effort for the development of an actual wind simulation method on the wind turbine performance evaluation. It should be emphasized that the deep knowledge on real wind field is a key factor for both the design of a wind turbine and the performance evaluation. With this reason, there had been several simulation attempts to accurately match with the actual wind data. With an existing wind generation algorithm is under consideration, this study introduces several more new concepts including Van der Hoven spectrum being implemented in different methodology. Also this paper will compare the result from the wind simulations by using the basic formula with that by using MATLAB and SIMULINK previously developed. In addition, like the existing wind generation algorithm, random process for actual wind field simulation and white noise are incorporated to closely produce the actual wind field models.

• Journal of Industrial Technology
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• v.22 no.A
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• pp.49-57
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• 2002

The accurate wind speed information at the hub height of a wind turbine is very essential to the exact estimation of the wind turbine power performance testing. Several methods on the site calibration, which is a technique to estimate the wind speed at the wind turbine's hub height based on the measured wind data using a reference meteorological mast, are introduced. A site calibration result and the wind resource assessment for the Taekwanryung test site are presented using a one-month wind data from a reference meteorological mast and a temporal mast installed at the site of wind turbine. From this analysis, it turns out that the current location of the reference meteorological mast is wrongly determined, and the self-developed codes for the site calibration are working properly. Besides, an analysis on the uncertainty allocation for the wind speed correction using site calibration is performed.

• New & Renewable Energy
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• v.3 no.1 s.9
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• pp.20-26
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• 2007

A low-resolution national wind map, which is a prerequisite for setting up the national dissemination target and strategy of wind energy development, has been established by numerical wind simulation using the synoptic wind map, developed at the first stage, as an upper boundary condition. Based on the wind map, Wind Resource Information System has been composed in order to support scientific and systematic wind resource assessment and analysis.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.59.1-59.1
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• 2011

In this research, CFD calculation was implemented to analyze wind tunnel effect or rotor experiment in wind tunnel. One case included model wind turbine and all wind tunnel geometries. The other case include only rotor and nacelle system. Star-CCM+ was used for CFD analysis and rigid body motion around rotor area was applied to simulate rotating rotor. As for turbulence model, K-omega SST was used. The results were compared in 15m/s inflow condition. These results shows a good agreement with the measurement. Then, the result without wind tunnel was slightly different to the result with wind tunnel. Thus, in the case of Mexnex wind tunnel measurement, the wind tunnel don't affect the measurement result. Then, this wind tunnel and rotor size ratio can be reference for wind tunnel experiment of wind turbine rotor.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.307-308
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• 2006

The national goal of wind energy dissemination has to be determined rationally based on technically available wind resource potential. For a reliable and scientific estimation or wind resource potential, a wind map is requisite. This paper presents the national wind map of Korea established by numerical wind simulation. Prediction accuracy of the low-resolution wind map is Improved by nudging QuikSCAT data and is validated by comparing with marine buoy beacon and met-mast measurements. Therefore, quantification of national wind resource potential is now possible and is anticipating to be utilized as a core index for policy and strategy building of wind energy dissemination and technology development.

• Journal of Environmental Impact Assessment
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• v.16 no.6
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• pp.503-510
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• 2007

Since 1990s many skyscrapers have been built in Seoul. However, gusty winds occur among tall buildings by descending turbulences due to the upper air blocking. This study aims to investigate the wind characteristics of skyscraper prevailing wind direction. In order to evaluate the building wind in this area, The wind speed and the wind direction were measured using propeller type RM-Young wind monitor in this study. The maximum wind speed was recorded by 15.1 m/sec and the main wind direction is WNW and NW. The ultimate purpose of this study is to figure out the phenomena of building wind impact and also to provide essential basic data for establishing proper guidelines in building wind impact assessment for skyscrapers in Korea.

• Wind and Structures
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• v.23 no.4
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• pp.351-366
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• 2016

Nowadays, wind energy is the most rapidly developing technology and energy source and it is reusable. Due to its cleanliness and reusability, there have been rapid developments made on transferring the wind energy systems to electric energy systems. Converting the wind energy to electrical energy can be done only with the wind turbines. So installing a wind turbine depends on the wind speed at that location. The expected wind power can be estimated using a perfect probability distribution. In this paper Weibull and Weibull distribution with multiple parameters has been used in deriving the mathematical expression for estimating the wind power. Statistically the parameters of Weibull and Weibull distribution are estimated using the maximum likelihood techniques. We derive a probability distribution for the power output of a wind turbine with given rated wind speeds for the regions where the wind speed histograms present a bimodal pdf and compute the first order moment of this distribution.

• Wind and Structures
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• v.19 no.5
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• pp.565-583
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• 2014

Using synchronous surface pressures from the wind tunnel test, the three dimensional wind load models of high-rise buildings are established. Furthermore, the internal force responses of symmetric high-rise buildings in along-wind, across-wind and torsional directions are evaluated based on mode acceleration method, which expresses the restoring force as the summation of quasi-static force and inertia force components. Accordingly the calculation methods of equivalent static wind loads, in which the contributions of the higher modes can be considered, of symmetric high-rise buildings in along-wind, across-wind and torsional directions are deduced based on internal forces equivalence. Finally the equivalent static wind loads of an actual symmetric high-rise building are obtained by this method, and compared with the along-wind equivalent static wind loads obtained by China National Standard.