Papers by Keyword: Wind Tunnel Test

Abstract: Wind-induced aerodynamic force is the important parameter for transmission tower design. Based on force balance test, the tower and cross arm of typical 500kV power transmission tower have been investigated in wind tunnel using three wind speeds considering Reynolds effect. The test results show that the shape coefficient keeps the same at different wind speed, which means that Reynolds effect on transmission tower can be ignored. Then, the shape coefficients of tower and cross arm are provided.

Abstract: Field measurement and wind tunnel test of wind pressure on the surfaces of Wuhan International Stock Building were carried out in this paper, and the mean wind pressure coefficients, RMS wind pressure coefficients, wind pressure spectra as well as coherence functions were discussed. Meanwhile wind pressure distributions were analyzed. The results demonstrated that the distribution of the surface mean wind pressure coefficients obtained by wind tunnel test approximately agreed with that by field measurement, especially the mean wind pressure coefficients on the windward obtained by the wind tunnel test fitted those obtained by the field measurement well, while the RMS wind pressure coefficients of the wind tunnel results are smaller than those of field measurement, and the RMS wind pressure coefficients of some measure points of field measurement fluctuated greatly.

Abstract: In response to the estimation of the peak values of wind pressure on the maintenance structure, the results with TTU low-rise building standard model of different methods are analyzed and compared. The results show: the results of peak-to-average method and Cook & Mayne method are very close for the long sample estimation of the peak values of wind pressure, the former is the most ideal method for estimation of extreme wind pressure; For short sample estimation, the peak-to-average method fails because the sampling is not long enough, but the Cook & Mayne method can estimate accurate peak value of wind pressure by the short sample (the corresponding prototype time not less than 600s); The peak factor method based on the assumption of normal distribution is not applicable to low-rise building and the results are relatively dangerous.

Abstract: As the significant difference in wind tunnel data between two scaled models of a practical engineering, the cause of this difference, which was regarded as blockage effect, was analyzed in this paper. Research shows that, for wind tunnel test with more surrounding buildings, blockage effect may result in serious data distortion, especially for lateral wind pressure, and existing correction method does not possess universality. Moreover, blockage ratio, as a global concept, is not appropriate to evaluate blockage effect of wind tunnel pressure data at different parts of building models. This study has reference value for blockage effect of wind tunnel pressure date in practical engineering.

Abstract: The aerodynamic forces of two typical iced conductor models are obtained by high frequency balance technique in wind tunnel test. The effects of wind directions and turbulence intensity on aerodynamic forces coefficients are discussed. An analytical expression for predicting the galloping instability trends in arbitrary directions is derived. An aerodynamic model considering the dynamic swing is developed according to the quasi-steady theory. Galerkins procedure is employed to discrete the governing equations of transmission line, which is modeled as a suspended homogeneous elastic cable having a small equilibrium curvature and neglecting the shear deformation. The forth order Runge-Kutta method are applied to obtained the approximate numerical results of iced transmission line galloping.

Abstract: A series of wind tunnel aerodynamic experiments were conducted to investigate the wind loads on the water tank located around the roof top of low-rise buildings with gable roof. There are two installation conditions discussed in this study, they were the alignment of tank and the location on roof. The result shown, the vertical tank might suffer less wind loading at each wind attack angle due to its symmetric shape. And the horizontal tank would have large wind loading in some approaching flow angles, especially in the 45 degrees attack angle the wind loading may reach its maximum. The variant location and roof slope were checked for the water tank installation, the results shown that the tank which installed at ridge region will suffer higher wind loadings and the border region of roof will be the recommended region for water tank installation.

Abstract: New-typedenergy-saving conductor can obviously increase conductor conductivity ability, and reduce the transmission losses. But for the changes of structure and surface properties, its load and the vibration impact characteristic are not enough comprehensive, so it is difficult to effectively guide the energy saving design of the conductor. Making use of the wind tunnel test, the aerodynamic character of various conductorsare obtained for single,double, four and six bundle conductor. The result of research is benefit for the far-ranging application of energy-saving conductor.

Abstract: For conductors commonly used in the high and ultra-high voltage transmission projects, research was conducted on how ice shape, ice thickness, wind speed and angle of attack affect the static aerodynamic characteristics of ice-coated conductor. The ice shape and the shape of ice-coated conductor are both important factors that determine the aerodynamic characteristics of conductor. Sudden increase of lift coefficient may happen at low angle of attack. Wind speed shows less effect on aerodynamic characteristics of ice-coated conductor with streamlined shape than that of conductor with blunt shape. Under most attack angles, aerodynamic coefficients increase as the ice thickness increases. The aerodynamic load on ice-coated conductor does not increase linearly with the diameter of conductor.

Abstract: As a new long-span suspension bridge with double main spans and a typical closed streamline cross-section of single box deck, the flutter performance of the Maanshan Bridge during erection was investigated via a full bridge aeroelastic model test. Critical flutter wind speeds of 13 testing cases with different percentage of deck completion are much higher than the flutter checking wind speeds, and the bridge is hence proven to be stable enough during erection in aerodynamics. The case with the percentage of deck completion of 86.4% gets the lowest flutter critical wind speed, perhaps because frequency ratio gets the minimum value at this case.

Abstract: A large number of buildings with large-span or complex-shape have come to the fore in recent years. To these structures, wind load tends to be control load in the structural design. Shape coefficient of wind load which Chinese load code for the design of building structures can provide is extremely limited due to complex-shape of long-span space structures, therefore carrying our related study is of great practical significance. Yancheng Financial Center model is established in this paper based on ETABS software. The acquired date in the use of wind tunnel test is to simulate wind load which is on the structure and to analysis stress distribution of critical element in order to ensure safety and applicability of structures. This paper mainly covers wind tunnel test, equivalent static wind load, and wind-induced response, etc.