• Title, Summary, Keyword: wind tunnel experiments

Search Result 203, Processing Time 0.041 seconds

The wind tunnel measuring methods for wind turbine rotor blades

  • Vardar, Ali;Eker, Bulent
    • Wind and Structures
    • /
    • v.7 no.5
    • /
    • pp.305-316
    • /
    • 2004
  • In this study, a wind tunnel, that has been developed for experiments of wind turbine rotor blades, has been considered. The deviations of the measurements have been examined after this wind tunnel had been introduced and the measurements on it had been explained. Two different wind turbine rotor blades miniatures have been used for getting better results from the experiments. The accuracy of measurements have been experimented three times repetitively and examined statistically. As a result, wind speed values which this type of wind tunnel and wind turbine rotors need for starting, wind speed in the tunnel, temperature and moisture values, the number of rotor's revolution, and the voltage that is produced in 102 ${\Omega}$ resistance and current values have been determined to be fixed by measurements used. This type of wind tunnel and wind turbine rotor' performance difference and the difference of revolution figures have been determined to be fixed by measurements used.

Wind-Resistant Safety Reviews of Cable-Stayed Bridge by Wind Tunnel Tests (풍동실험을 통한 사장교의 내풍 안전성 검토)

  • Huh, Taik-Nyung
    • Journal of the Korean Society of Industry Convergence
    • /
    • v.23 no.4_2
    • /
    • pp.637-644
    • /
    • 2020
  • Because suicide accidents sometimes were happened in grand bridges over rivers or sea water recently, it will be necessary that prevention measures be made preparation in advance from now on. Additional safety facilities must be needed in addition to existing safety facilities in such a way as this prevention measure. In order to make cable-stayed bridge safe on wind for additional safety facilities, main girder models with added safety facilities for wind-tunnel tests was made, and wind tunnel experiments was carried out to measure aerodynamic force coefficients. Also, wind-resistant analyses of 3D cable-stayed bridge were performed on the basis of wind-tunnel test results. From the wind experiments, force coefficients of main girder with added safety facilities were assessed, and it is known that there are little possibility of galloping and rotation of steel main girder. Finally, from the wind resistant analyses, it was concluded that wind-resistant safety of cable-stayed bridge was secured on wind speed 60.6m/sec.

A GUIDE FOR NUMERICAL WIND TUNNEL ANALYSIS IN ORDER TO PREDICT WIND LOAD ON A BUILDING (건축물의 풍하중을 예측하기 위한 수치풍동기법)

  • Lee, Mung-Sung;Lee, June-Hee;Hur, Nahm-Keon;Choi, Chang-Koon
    • 한국전산유체공학회:학술대회논문집
    • /
    • /
    • pp.5-9
    • /
    • 2010
  • A numerical wind tunnel simulation is performed in order to predict wind loads acting on a building. The aim of the present study is to suggest a guideline for the numerical wind tunnel analysis, which could provide more detail wind load distributions compared to the wind code and expensive wind tunnel experiments. To validate the present numerical simulation, wind-induced loads on a 6 m cube model is predicted. Atmospheric boundary layer is used as a inlet boundary condition. Various effect of numerical methods are investigated such as size of computational domain, grid density, turbulence model and discretization scheme. The appropriate procedure for the numerical wind tunnel analysis is suggested through the present study.

  • PDF

Wind tunnel experiments of a building model incorporating viscous-damping walls

  • Pan, Austin D.E.;Yeung, Ngai
    • Wind and Structures
    • /
    • v.4 no.3
    • /
    • pp.261-276
    • /
    • 2001
  • This paper presents an experimental study on the effectiveness of viscous-damping walls in controlling the wind-induced vibrations of a building model. A simple four-story building model, square in plan, was constructed for wind tunnel study. In this paper the description of the model, its instrumentation, and the experimental set-up and methodology are reported. The effectiveness of viscous-damping walls in reducing vibrations was investigated for different fluid levels in the walls, and at varying wind speeds and attack angles. The results show that viscous-damping walls are highly effective in most cases.

Comparison between wind load by wind tunnel test and in-site measurement of long-span spatial structure

  • Liu, Hui;Qu, Wei-Lian;Li, Qiu-Sheng
    • Wind and Structures
    • /
    • v.14 no.4
    • /
    • pp.301-319
    • /
    • 2011
  • The full-scale measurements are compared with the wind tunnel test results for the long-span roof latticed spatial structure of Shenzhen Citizen Center. A direct comparison of model testing results to full-scale measurements is always desirable, not only in validating the experimental data and methods but also in providing better understanding of the physics such as Reynolds numbers and scale effects. Since the quantity and location of full-scale measurements points are different from those of the wind tunnel tests taps, the weighted proper orthogonal decomposition technique is applied to the wind pressure data obtained from the wind tunnel tests to generate a time history of wind load vector, then loads acted on all the internal nodes are obtained by interpolation technique. The nodal mean wind pressure coefficients, root-mean-square of wind pressure coefficients and wind pressure power spectrum are also calculated. The time and frequency domain characteristics of full-scale measurements wind load are analyzed based on filtered data-acquisitions. In the analysis, special attention is paid to the distributions of the mean wind pressure coefficients of center part of Shenzhen Citizen Center long-span roof spatial latticed structure. Furthermore, a brief discussion about difference between the wind pressure power spectrum from the wind tunnel experiments and that from the full-scale in-site measurements is compared. The result is important fundament of wind-induced dynamic response of long-span spatial latticed structures.

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

  • Kozmar, Hrvoje
    • Wind and Structures
    • /
    • v.14 no.1
    • /
    • pp.15-34
    • /
    • 2011
  • 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.

An Experimental Study on Smoke Movement by the External Wind in Road Tunnel Fires (도로터널 화재 시 외부 바람에 의한 연기거동 특성에 관한 실험적 연구)

  • Lee, Sung-Ryong
    • Tunnel and Underground Space
    • /
    • v.24 no.4
    • /
    • pp.308-315
    • /
    • 2014
  • In this study, reduced scale experiments were carried out to evaluate the effect of external wind in a road tunnel fire. Experiments were conducted in a $1.1m{\times}0.5m{\times}50.4m$ tunnel. 4.5 litter gasoline was used as a fuel. Temperature, oxygen and carbon monoxide concentration were measured. Smoke reaching time to the tunnel exit was affected by the external wind. When a fire was fully developed, wind effect is reduced compared with the early stage of a fire. CO concentration was reached at more than 1,500 ppm.

Wind tunnel blockage effects on aerodynamic behavior of bluff body

  • Choi, Chang-Koon;Kwon, Dae-Kun
    • Wind and Structures
    • /
    • v.1 no.4
    • /
    • pp.351-364
    • /
    • 1998
  • In wind tunnel experiments, the blockage effect is a very important factor which affects the test results significantly. A number of investigations into this problem, especially on the blockage correction of drag coefficient, have been carried out in the past. However, only a limited number of works have been reported on the wind tunnel blockage effect on wind-induced vibration although it is considered to be fairly important. This paper discusses the aerodynamic characteristics of the square model and square model with corner cut based on a series of the wind tunnel tests with various blockage ratios and angles of attack. From the test results, the aerodynamic behavior of square models with up to 10% blockage ratio are almost the same and square models with up to 10% blockage ratio can be tested as a group which behaves similarly.

Characteristic of Wind Flow around Building Structures for Wind Resource Assessment (풍자원 평가를 위한 건축물 주변의 유동특성)

  • Cho, Kang-Pyo;Jeong, Seung-Hwan;Shin, Seung-Hwa
    • The KSFM Journal of Fluid Machinery
    • /
    • v.14 no.3
    • /
    • pp.50-58
    • /
    • 2011
  • To utilize wind resources effectively around buildings in urban area, the magnitudes of wind velocity and turbulence intensity are important, which means the need of the information about the relationship between the magnitude of wind velocity and that of fluctuating wind velocity. In the paper, wind-tunnel experiments were performed to provide the information about Characteristic of Wind flow around buildings with the spanwise distance and the side ratio of buildings as variables. For a single building with the side ratios of one and two, the average velocity ratio was 1.4 and the velocity standard deviation ratio ranged from 1.4 to 2.6 at the height of 0.02m at the corner of the windward side, in which flow separation occurred. For twin buildings with the side ratios of one and two, the velocity ratio ranged from 2 to 2.5 as the spanwise distance varied at the height of 0.02m, and the velocity standard deviation ratio varied near 1.25. For twin buildings with the side ratios of one and two, the maximum velocity ratio was 1.75 at the height of 0.6m, and the maximum velocity standard deviation ratio was 2.1. It was also found from the results of CFD analysis and wind-tunnel experiments that for twin buildings with the side ratios of one and two, the difference between the velocity ratio of CFD analysis and that of wind-tunnel experiments at streamwise distances was near 0.75.

Wind pressure characteristics for a double tower high-rise structure in a group of buildings

  • Tse, K.T.;Wang, D.Y.;Zhou, Y.
    • Wind and Structures
    • /
    • v.16 no.5
    • /
    • pp.491-515
    • /
    • 2013
  • Wind pressure characteristics on a double tower high-rise structure, which is disturbed by surrounding buildings, were investigated using large eddy simulation (LES) and 1:300 scale wind tunnel experiments. The computational simulation technique and wind tunnel experimental technique were described in detail initially. Comparisons of computational results with the experimental data have subsequently been carried out to validate the reliability of LES. Comparisons have been performed in detail for the mean and fluctuating pressure coefficients. Detailed explanations of each comparison were given in the paper. To study further on the pressure coefficients on the building surfaces, parametric studies on shape coefficient and spatial correlation were performed and investigated. The numerical and experimental results presented in this paper advance understanding on wind field around buildings and the application of LES and wind tunnel tests.