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Liu Q.,Shijiazhuang University | Liu Q.,Hebei Province Key Laboratory of Structural Health Monitoring and Control | Shao Q.,Shijiazhuang University | Zheng Y.,Shijiazhuang University | And 5 more authors.
Shiyan Liuti Lixue/Journal of Experiments in Fluid Mechanics | Year: 2016

By wind tunnel tests, Reynolds number effect on drag force coefficient, lift force coefficient and wind pressure coefficient of cylinder were measured, the mechanism of the aerodynamic force variation from the point of view of the flow field distribution was analyzed, and the correlation of the flow field in the cylinder axis direction under the Reynolds number effect was studied. Results show that in the subcritical Reynolds number regime, the time averaged flow field around the cylinder model is symmetric, the Reynolds number has little influence on the averaged drag force coefficient and flow field, and the averaged lift force is around zero. In the critical Reynolds number regime, with the appearance of large amplitude negative pressure in certain areas, flow field becomes asymmetric, and the averaged lift force as well as fluctuation lift force appears. In the supercritical Reynolds number regime, with the appearance of large amplitude negative pressure on the two sides, flow field becomes to symmetric again, and the averaged lift force disappears. Reynolds number has obvious effect on the flow field correlation along the cylinder axis. In the subcritical Reynolds number regime, the scale of the Karman vortex in the cylinder axis direction is relatively large, while the scale becomes small with the increase of Reynolds number. © 2016, Editorial Department of JOURNAL OF EXPERIMENTS IN FLUID MECHANICS. All right reserved.


Bai Y.-R.,Shijiazhuang University | Zhao S.-B.,Shijiazhuang University | Liu Q.-K.,Shijiazhuang University | Liu Q.-K.,Hebei Province Key Laboratory of Structural Health Monitoring and Control | And 4 more authors.
Gongcheng Lixue/Engineering Mechanics | Year: 2015

Helical lines wrapped on a cable surface are regarded as an effective aerodynamic measure to control the rain-wind induced vibration of cables. By simulated rainfall wind tunnel tests, the effect of the parameters of a helical line diameter, the space, and the wrapping method on rain-wind induced vibration control were studied. Using non-dimensional parameters of the helical line diameter and space, the relation between these two parameters and vibration amplitude were obtained. The results provide a reference for cable design. ©, 2015, Tsinghua University. All right reserved.


Li X.-N.,Shijiazhuang University | Lu Y.,Shijiazhuang University | Liu Q.-K.,Shijiazhuang University | Liu Q.-K.,Hebei Province Key Laboratory of Structural Health Monitoring and Control | And 4 more authors.
Gongcheng Lixue/Engineering Mechanics | Year: 2015

Circular section chimneys in large thermal power plants are typical high-rise wind-sensitive structures. Wind load is one of the governing loads in chimney design. In this study the pressure distribution on a single chimney under different wind angles and two chimneys arranged in series and parallel was investigated using wind tunnel tests. Results show that when two chimneys are in series, the wind pressure coefficient of the downstream one is small and the sheltering effect is obvious. When two chimneys are in parallel, the lower parts of the chimneys show interference effects, and the channeling effects become more prominent. ©, 2015, Tsinghua University. All right reserved.


Liu X.-B.,Shijiazhuang University | Liu X.-B.,Hebei Province Key Laboratory of Structural Health Monitoring and Control | Zhang H.-D.,Shijiazhuang University | Wang Y.-B.,Shijiazhuang University
Gongcheng Lixue/Engineering Mechanics | Year: 2015

A pressure-measured sectional model wind tunnel test of a rectangular cylinder with aspect ratio 5 was performed. The changing rule for the spanwise correlation of an aerodynamic force versus a spanwise distance and a wind attacking angle was studied. The study results show that the spanwise correlation coefficient of an aerodynamic force becomes smaller with a larger spanwise distance. Under the same spanwise distance, the spanwise correlation coefficient of a lift force is greatest, the spanwise correlation coefficient of a torque is smaller, and the spanwise correlation coefficient of a drag force is smallest. The spanwise correlation coefficient between a lift force and a torque attains the maximum value in a zero degree wind attacking angle, and it becomes smaller with a larger wind attacking angle. ©, 2015, Tsinghua University. All right reserved.


Shi C.,Shijiazhuang University | Li Z.-Y.,Shijiazhuang University | Liu Q.-K.,Shijiazhuang University | Liu Q.-K.,Hebei Province Key Laboratory of Structural Health Monitoring and Control
Gongcheng Lixue/Engineering Mechanics | Year: 2015

Non-uniform distribution of snow caused by snowdrift may result in structural damage in snow and wind areas. In order to obtain the simulation and test methods of snowdrift for engineering practice, wind tunnel tests and field observations were used to carry out preliminary research. By wind tunnel tests, we investigated the changing of accumulating thickness of simulating materials with time and wind velocity, and moreover, the effect of bond force on tests results. By field observation, the snow distribution on stepped flat roofs was measured and compared with former research. ©, 2015, Tsinghua University. All right reserved.


Qin Q.-W.,Shijiazhuang University | Liu X.-B.,Shijiazhuang University | Liu X.-B.,Hebei Province Key Laboratory of Structural Health Monitoring and Control | Liu Q.-K.,Shijiazhuang University | Liu Q.-K.,Hebei Province Key Laboratory of Structural Health Monitoring and Control
Gongcheng Lixue/Engineering Mechanics | Year: 2016

There are many engineering structures with circular sections. At regular wind speed, the Reynolds number of these structures can reach 107 or more which falls into high supercritical Reynolds number region. However, researches on circular cylinder in this region are few. Based on this situation, the wind load of a single circular cylinder of 5 meters in diameter is studied by numerical calculation. The computational domain, number of circumjacent grid, height of the first normal layer grid and computational time step are examined. The drag coefficient and the flow field distribution around the circular cylinder are obtained. © 2016, Engineering Mechanics Press. All right reserved.


Liu X.-B.,Shijiazhuang University | Liu X.-B.,Hebei Province Key Laboratory of Structural Health Monitoring and Control | Zhang H.-D.,Shijiazhuang University | Wang Y.-B.,Shijiazhuang University
Gongcheng Lixue/Engineering Mechanics | Year: 2016

A sectional model wind tunnel test of a flat box girder in smooth flow was performed and the spanwise correlation of vortex-induced forces was investigated. The study results show that spanwise correlation of lift force becomes weakened with the decrease of vibration amplitudes at vibration amplitude-decreasing stage in lock-in range. At vibration amplitude-increasing stage in lock-in range, with the increase of vibration amplitudes, spanwise correlation of lift force becomes strengthened first and then weakened. The maximum value of spanwise correlation coefficient appears in a wind speed in vibration amplitude-increasing stage, rather than the wind speed corresponding to maximum vibration amplitude; In lock-in range, spanwise correlation of vortex-induced forces of flat box girder is dependent on both vibration amplitude and wind speed in smooth flow. © 2016, Engineering Mechanics Press. All right reserved.


Liu Q.-K.,Shijiazhuang University | Liu Q.-K.,Hebei Province Key Laboratory of Structural Health Monitoring and Control | Zheng Y.-F.,Shijiazhuang University | Liu X.-B.,Shijiazhuang University | And 3 more authors.
Gongcheng Lixue/Engineering Mechanics | Year: 2015

Stay-cables are main stressed members of cable-stayed bridges, as the most part of wind loads on a cable-stayed bridge is caused by its cables, it is very important to master the wind forces on cables exactly for bridge design. At the same time, as wind induced cable vibrations happen frequently and cause serious damage to bridges, the mechanisms of vibration are hot problems in the research work of wind engineering, and vibration control methods are key issues to be considered in bridge design. In this paper, wind load calculating methods, types of wind induced vibrations and mechanisms of cables are introduced, and the research achievements of vibration control methods designed from aerodynamic perspective are summarized. It provides a reference for the designing work of vibration control and relevant mechanism research of cables. ©, 2015, Tsinghua University. All right reserved.

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