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为研究箱梁断面产生双竖向涡振区的原因,通过同步测振和测压均匀风场风洞试验,基于涡振区的振幅响应与表面压力脉动时程,分析了2个竖向涡振区的振幅与风速关系、表面压力系数均值与均方差值、局部升力与总升力的相关性及局部升力对竖向涡振的贡献。分析结果表明:高风速涡振区比低风速涡振区锁定区间长、振动响应大;低风速涡振区的Strouhal数为0.145,高风速涡振区的Strouhal数为0.082,2个竖向涡振区是由具有不同Strouhal数的2个独立气流涡脱所致;低风速涡振区涡激力主要来源于箱梁上表面中部2道防护栏区域和下表面背压区的气流脉动,高风速涡振区涡激力主要来源于箱梁上表面下游区域和下表面背压区的气流脉动,两者在上表面的气流涡脱相互独立。研究成果对典型钝体箱梁断面有一定的普遍适用性,研究方法可为类似研究提供借鉴。
In order to study the reason of double vertical vortex vibration in the section of box girder, by means of synchronous vibration measurement and uniform pressure wind tunnel test, based on the amplitude response of vortex vibration region and surface pressure pulsation time history, two vertical vortexes The relationship between amplitude and wind speed of vibration zone, the mean and mean square error of surface pressure coefficient, the correlation between local lift and total lift and the contribution of local lift to vertical vortex vibration. The analysis results show that the vortex vibration region of high wind speed is longer than that of the low wind velocity vortex vibration region and the vibration response is large. The Strouhal number of vortex vibration region in low wind velocity is 0.145, Strouhal number of high wind vortex vibration region is 0.082, The vortex area is caused by two independent airflow vortices with different Strouhal numbers. The vortex-induced vibration in low vorticity vortex area mainly comes from the pulsation of air flow in the two guardrail areas and the back pressure area in the lower surface of the upper surface of the box beam, Vortex-induced vortices in the wind vortex are mainly originated from the pulsation of the air flow in the downstream area of the upper surface of the box girder and in the back-pressure area of the lower surface, and the eddy currents of the two surfaces are independent of each other. The research results have certain general applicability to typical bluff box girder section, and the research methods can provide reference for similar research.