锥状涡作用下大跨度平屋盖表面脉动风压谱模型研究

发布时间：2018-02-14 23:56

  本文关键词： 平屋盖 风洞试验 锥状涡 风压谱模型　出处：《土木工程学报》2014年01期 　论文类型：期刊论文

【摘要】：锥状涡是大跨度平屋盖表面在斜风向来流作用下形成的一种特征湍流形式,相对于来流垂直于檐口时所形成的柱状涡而言,锥状涡的作用形态更为复杂,破坏性更强。基于风洞测压试验,对锥状涡作用下平屋盖表面不同位置处的脉动风压谱特性进行研究,探讨脉动风压谱形状与分离、再附、漩涡脱落等流动现象之间的联系,归纳出四类典型的脉动风压谱形式;在此基础上,提出由来流湍流影响项和特征湍流影响项组成的脉动风压谱多项式模型,并通过引入权重系数来反映不同湍流影响项的贡献。研究结果表明,通过权重系数的分布可以划分流场影响区域,具有一定的物理意义。同时考察脉动风压的空间相关性,研究表明,在锥形涡作用使得屋盖表面脉动风压相关性强于来流脉动风速,相干函数用指数衰减函数表示,衰减系数可取2.5。最后,通过风振响应分析结果来比较风压谱模型对风振响应结果的影响,结果表明,拟定常假设低估了结构的脉动响应,而基于文中的简化风压谱模型得到的风振响应结果与风洞试验结果吻合较好。研究为进一步建立统一的屋盖脉动风压谱模型奠定了基础。
[Abstract]:Conical vortex is a characteristic turbulent form formed on the surface of a large span flat roof under the action of oblique wind flow. Compared with the columnar vortex formed when the incoming flow is perpendicular to the cornice, the action pattern of the conical vortex is more complicated than that of the column vortex formed when the flow is perpendicular to the cornice. On the basis of wind tunnel pressure measurement test, the characteristics of fluctuating wind pressure spectrum at different positions on the surface of flat roof under the action of conical vortex are studied, and the relationship between the shape of fluctuating wind pressure spectrum and flow phenomena such as separation, reattachment and vortex shedding is discussed. Four typical types of fluctuating wind pressure spectrum are summarized, and a polynomial model of pulsating wind pressure spectrum is proposed, which is composed of the turbulent influence term and the characteristic turbulence influence term. The results show that the distribution of the weight coefficients can be used to divide the affected areas of the flow field, which is of certain physical significance. At the same time, the spatial correlation of the pulsating wind pressure is investigated. The results show that the correlation of fluctuating wind pressure on the roof surface is stronger than that of the incoming wind velocity under the action of conical vortex. The coherence function is expressed by exponential attenuation function, and the attenuation coefficient is 2.5. Finally, The effect of wind pressure spectrum model on wind-induced vibration response is compared by the results of wind vibration response analysis. The results show that the proposed assumptions underestimate the fluctuating response of the structure. The results of wind vibration response based on the simplified wind pressure spectrum model in this paper are in good agreement with the wind tunnel test results. The study lays a foundation for the further establishment of a unified roof fluctuating wind pressure spectrum model.
【作者单位】： 哈尔滨工业大学;
【基金】：国家自然科学基金面上项目(51278160,50908068)、国家自然科学基金重大研究计划集成项目(91215302) 中国博士后科学基金(20110491079)
【分类号】：TU312.1
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本文编号：1511926