摘要
柱状涡和锥形涡是低矮建筑表面常见的两种破坏性旋涡。这两种旋涡将在屋盖表面局部诱导产生强风吸力,会使结构整体失效。因此,为减少低矮建筑的风致破坏,应对其表面旋涡及诱导的风压特性进行研究。通过调研相关文献,对旋涡形态特征、旋涡诱导的风压分布特性以及旋涡作用下强风吸力产生机理三个方面的研究现状进行了总结。结果表明:柱状涡和锥形涡在低矮建筑屋面诱导的风压分布可分别采用相应的拟合公式进行统一表达;其诱导下的风压脉动特性大多通过幅值分析(时域)和能量分析(频域)获得。为了探讨旋涡诱导下强风吸力的产生机理,基于风洞试验所测得的风压数据,研究其时域及频域特征;并结合旋涡理论,对旋涡作用机理给出间接的理论推测。此外,亦有学者通过测量旋涡截面流速,对现有旋涡模型进行改进,据此分析旋涡作用与涡下吸力的量化关系。
Columnar vortex and conical vortices are two destructive vortices frequently occurred on low-rise buildings.Under their influence,local intense suctions are induced on roofs of low-rise buildings,and finally the whole buildings encounter failure.Therefore,in order to reduce the loss of low-rise buildings caused by wind load,comprehension of vortices and the induced wind pressures is the primary task.A series of research have been conducted at home and abroad.In this paper,researches on characteristics of vortices,the vortex-induced wind pressures and the generation mechanism of severe suction under vortices are investigated and summarized.Results indicate that wind pressures distributions induced by columnar vortex and conical vortices can be represented by respective fitting equation.Characteristics of vortex-induced pressure fluctuations are usually investigated on time and frequency domain.In order to obtain the generation mechanism of severe suction,characteristics of measured wind pressures in time and frequency domain,combined with the vortex theory,are used to deduce the mechanism.Furthermore,researches have been conducted to measure the velocity in vortices so as to improve the existing vortex model.Based on this,preliminary investigations of the quantitative relationship between the vortices and the induced peak suctions have been carried out.
引文
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