• Wind and Structures
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• v.20 no.6
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• pp.739-749
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• 2015

Field measurement of wind characteristics is of great significance for the wind engineering community. High-frequency anemometers such as ultrasonic anemometers are widely used to obtain the high-frequency fluctuating wind speed time history. However, conventional instrumentation systems may suffer from low efficiency, non-real time transmission and higher maintenance cost, and thus are not very appropriate in the field measurement of strong winds in remote areas such as mountain valleys. In order to improve the field measurement performance in those remote areas, a wireless high-frequency anemometer instrumentation system for field measurement has been developed. In this paper, the architecture of the proposed instrumentation system, and measured data transmission and treatment will be presented firstly. Then a comparison among existing instrumentation systems and the proposed one is made. It shows that the newly-developed system has considerable advantages. Furthermore, the application of this system to the bridge site located in the mountain valley is discussed. Finally, typical samples of measured data from this area are presented. It can be expected that the proposed system has a great application potential in the wind field measurement for remote areas such as the mountainous or island or coastal area, and hazardous structures such as ultra-voltage transmission tower, due to its real-time transmission, low cost and no manual collection of data and convenience.

• Structural Engineering and Mechanics
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• v.76 no.2
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• pp.269-278
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• 2020

In this paper, the mechanical characteristics of the open type hyperbolic-parabolic membrane structure under wind load were investigated. First, the numerical simulation of a typical plane membrane structure was performed based on the Large-Eddy Simulation method. The accuracy of the simulation method was validated by the corresponding wind tunnel test results. Then, the wind load shape coefficients of open type hyperbolic-parabolic membrane structures are obtained from the series of numerical calculations and compared with the recommended values in the "Technical Specification for Membrane Structures (CECS 158: 2015). Finally, the influences of the wind directions and wind speeds on the mean wind pressure distribution of open type hyperbolic-parabolic membrane structures were investigated. This study aims to gain a better understanding of the wind-induced response for this type of structure and be useful to engineers and researchers.

• Wind and Structures
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• v.23 no.4
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• pp.313-350
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• 2016

Taipei 101 Tower, which has 101 stories with height of 508 m, is located in Taipei where typhoons and earthquakes commonly occur. It is currently the second tallest building in the world. Therefore, the dynamic performance of the super-tall building under strong wind actions requires particular attentions. In this study, Large Eddy Simulation (LES) integrated with a new inflow turbulence generator and a new sub-grid scale (SGS) model was conducted to simulate the wind loads on the super-tall building. Three-dimensional finite element model of Taipei 101 Tower was established and used to evaluate the wind-induced responses of the high-rise structure based on the simulated wind forces. The numerical results were found to be consistent with those measured from a vibration monitoring system installed in the building. Furthermore, the equivalent static wind loads on the building, which were computed by the time-domain and frequency-domain analysis, respectively, were in satisfactory agreement with available wind tunnel testing results. It has been demonstrated through the validation studies that the numerical framework presented in this paper, including the recommended SGS model, the inflow turbulence generation technique and associated numerical treatments, is a useful tool for evaluation of the wind loads and wind-induced responses of tall buildings.

• Wind and Structures
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• v.20 no.2
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• pp.213-236
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• 2015

For high-speed railways (HSR) in wind prone regions, wind barriers are often installed on bridges to ensure the running safety of trains. This paper analyzes the effect of wind barriers on the running safety of a high-speed train to cross winds when it passes on a bridge. Two simply-supported (S-S) PC bridges in China, one with 32 m box beams and the other with 16 m trough beams, are selected to perform the dynamic analyses. The bridges are modeled by 3-D finite elements and each vehicle in a train by a multi-rigid-body system connected with suspension springs and dashpots. The wind excitations on the train vehicles and the bridges are numerically simulated, using the static tri-component coefficients obtained from a wind tunnel test, taking into account the effects of wind barriers, train speed and the spatial correlation with wind forces on the deck. The whole histories of a train passing over the two bridges under strong cross winds are simulated and compared, considering variations of wind velocities, train speeds and without or with wind barriers. The threshold curves of wind velocity for train running safety on the two bridges are compared, from which the windbreak effect of the wind barrier are evaluated, based on which a beam structure with better performance is recommended.

• Wind and Structures
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• v.24 no.3
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• pp.205-221
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• 2017

The unsteady flow field disturbance between the blades and tower is one of the primary factors affecting the aerodynamic performance of wind turbine. Based on the research object of a 3MW horizontal axis wind turbine which was developed independently by Nanjing University of Aeronautics and Astronautics, numerical simulation on the aerodynamic performance of wind turbine system in halt state with blades in different position was conducted using large eddy simulation (LES) method. Based on the 3D unsteady numerical simulation results in a total of eight conditions (determined by the relative position with the tower during the complete rotation process of the blade), the characteristics of wind pressure distributions of the wind turbine system and action mechanism of surrounding flow field were analysed. The effect of different position of blades on the aerodynamic performance of wind turbine in halt state as well as the disturbance effect was evaluated. Results of the study showed that the halt position of blades had significant effect on the wind pressure distribution of the wind turbine system as well as the characteristics of flow around. Relevant conclusions from this study provided reference for the wind-resistant design of large scale wind turbine system in different halt states.

• Wind and Structures
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• v.38 no.2
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• pp.129-146
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• 2024

Aiming at the problem of non-stationary wind field simulation of downbursts, a non-stationary down-burst generation system was designed by adding a nozzle and program control valve to the inlet of the original wall jet model. The computational fluid dynamics (CFD) method was used to simulate the downburst. Firstly, the two-dimensional (2D) model was used to study the outflow situation, and the database of working conditions was formed. Then the combined superposition of working conditions was carried out to simulate the full-scale measured downburst. The three-dimensional (3D) large eddy simulation (LES) was used for further verification based on this superposition condition. Finally, the wind tunnel test is used to further verify. The results show that after the valve is opened, the wind ve-locity at low altitude increases rapidly, then stays stable, and the wind velocity at each point fluctuates. The velocity of the 2D model matches the wind velocity trend of the measured downburst well. The 3D model matches the measured downburst flow in terms of wind velocity and pulsation characteris-tics. The time-varying mean wind velocity of the wind tunnel test is in better agreement with the meas-ured time-varying mean wind velocity of the downburst. The power spectrum of fluctuating wind ve-locity at different vertical heights for the test condition also agrees well with the von Karman spectrum, and conforms to the "-5/3" law. The vertical profile of the maximum time-varying average wind veloci-ty obtained from the test shows the basic characteristics of the typical wind profile of the downburst. The effectiveness of the downburst generation system is verified.

• Wind and Structures
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• v.27 no.4
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• pp.213-221
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• 2018

In the desert and Gobi regions with strong wind and large sediment discharge, sand transporting engineering is more effective than sand blocking and sand fixing measures in sand prevention. This study uses the discrete phase model of 3D numerical simulation to study the motion trail, motion state and distribution rule of sand particles with different grain diameters when the included angle between the main shaft of the feather-row lateral transportation sand barrier and the wind direction changes, and conducts a comparison in combination with the wind tunnel test and the flow field rule of common sand barrier. According to the comparison, when wind-sand incoming flow passes through a feather-row sand barrier, sand particles slow down and deposit within the deceleration area under the resistance of the feather-row sand barrier, move along the transportation area formed by the transportation force, and accumulate as a ridge at the tail of the engineering. With increasing wind speed, the eolian erosion of the sand particles to the ground and the feather-row sand barrier is enhanced, and the sand transporting quantity and throw-over quantity of the feather-row sand barrier are both increased. When sand particles with different grain diameters bypass the feather-row sand barrier, the particle size of the infiltrating sands will increase with the included angle between the main shaft of the feather-row sand barrier and the wind direction. The obtained result demonstrates that, at a constant wind speed, the flow field formed is most suitable for the lateral transportation of the wind-drift flow when the included angle between the main shaft of the feather-row sand barrier lateral transportation engineering and the wind speed is less than or equal to $30^{\circ}$.

• Wind and Structures
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• v.30 no.6
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• pp.559-573
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• 2020

This paper presents a study on the effectiveness of the proper orthogonal decomposition (POD) technique for reconstruction of wind pressure field as applied to a cylindrical shell roof based on simultaneously measured wind pressure data. The influence of wind loading mode truncation on the statistics of dynamic pressures and wind load effects are investigated. The results showed that truncation of higher wind loading modes can have more noticeable influence on the maximum and minimum pressures that the standard derivation (STD) values. The truncation primarily affects the high-frequency content of the pressures. Estimation of background response using wind loading modes is more effective than the use of traditional structural modal analysis.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.918-922
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• 2016

As the number of wind farms operating has increased, the interest of the central unit commitment and dispatch for wind power has increased as well. Wind power forecast is necessary for effective power system management and operation with high wind power penetrations. This paper presents the centralized wind power forecasting method, which is a forecast to combine all wind farms in the area into one, using time series models. Also, this paper proposes a prediction model modified with wind forecast error compensation. To demonstrate the improvement of wind power forecasting accuracy, the proposed method is compared with persistence model and new reference model which are commonly used as reference in wind power forecasting using Jeju Island data. The results of case studies are presented to show the effectiveness of the proposed wind power forecasting method.

• Journal of the Korean Solar Energy Society
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• v.27 no.1
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• pp.1-9
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• 2007

This paper reveals both the operational situation and the cause of the error occurred in wind turbine generator system of Hangwon wind farm in Jeju island. The four wind turbines were selected for this work, and the monitored period was for six months. Wind resource in the wind farm was analyzed, and the estimated energy production was compared with the actual energy production. As a result, with a decrease of system error, the estimated energy production was in good agreement with the actual energy production. The errors occurring in components such as gearbox and hydraulic motor affected the Availability of the wind turbine. Also, poor external conditions such as a strong wind, lightning and gust caused a standstill of wind turbines.