The difference between aerodynamic forces and vibration characteristics of structures in unsteady wind and those in steady wind is a subject worth studying. In boundary layer wind tunnel, increasing wind and decreasing wind were generated with certain wind acceleration by voltage control. Aerodynamic forces and vibration amplitude were measured in both unsteady wind and steady wind. Experiment results show that the aerodynamic force coefficients in increasing wind calculated through instantaneous wind velocity and aerodynamic force are almost the same with the results in steady wind. Although the value of aerodynamic force coefficients in decreasing wind calculated through instantaneous wind velocity and aerodynamic force are almost the same with the results in steady wind, the critical Reynolds number range in decreasing wind offsets a certain value and becomes smaller compared with the critical Reynolds number range in steady wind. Unsteady wind will not induce large amplitude vibration when its velocity is outside the critical Reynolds number range. When wind velocity increases or decreases to the critical Reynolds number range, large amplitude vibration will occur. When wind velocity crosses the critical Reynolds number range, large amplitude vibration will occur when corresponding Reynolds number is in critical range and vibration will disappear when corresponding Reynolds number departs from critical range
LIU Qing-kuan; ZHANG Feng; WANG Yi; MA Wen-yong .
Experimental study on aerodynamic characteristics of circular cylinder in unsteady wind[J]. Journal of Vibration and Shock, 2012, 31(2): 62-66
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