Investigation of the flow structure of single- and dual-celled tornadoes and their wind effects on a dome structure
Investigation of the flow structure of single- and dual-celled tornadoes and their wind effects on a dome structure
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DOI：
10.1016/j.engstruct.2019.109999
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发表时间：
2020-04
影响因子：
5.5
通讯作者：
Tiantian Li;G. Yan;R. Feng;X. Mao
中科院分区：
文献类型：
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作者：
Tiantian Li;G. Yan;R. Feng;X. Mao
由于每年龙卷风造成的巨大财产损失和重大人员伤亡，龙卷风的研究引起了人们的广泛关注。然而，以往的研究主要集中在单胞流结构龙卷风的风场特征上，对双胞流结构龙卷风的研究较少。此外，龙卷风的气流结构对其风效应的影响还没有得到充分的探讨。因此，本研究的目的是研究如何在流动结构的细胞数量影响风的影响，通过计算流体动力学（CFD）模拟作用在土木结构。本文重点研究了单涡龙卷风的单胞和双胞流场结构，这两种结构都属于单涡龙卷风的范畴。为完整起见，本文也对两种龙卷风的风场特征进行了研究和比较。应用CFD模拟策略进行验证的基础上，现实世界的龙卷风。结果表明，由于中心下沉气流的存在，双胞龙卷风的湍流强度比单胞龙卷风的湍流强度大。双胞龙卷风的压力分布有一个宽而平坦的分布，而单胞龙卷风的压力分布则有一个窄而单峰的分布。由单胞龙卷风引起的两个拖曳力遵循一个典型的趋势，即，当穹顶中心移动到龙卷风核心半径时，它们达到最大值，而双胞龙卷风下相应的变化更趋于随机。从两个倾覆力矩中可以发现类似的观察结果。这表明双胞龙卷风引起的风荷载比单胞龙卷风引起的风荷载更具动态性。
Due to the incredible property loss and significant fatalities induced by tornadoes each year, tornado research has attracted considerable attention. However, previous studies mainly focused on the wind characteristics of tornadoes with the single-cell flow structure, and only a few targeted tornadoes with the dual-cell flow structure. In addition, the influence of flow structure of the tornado on its wind effects has not been sufficiently explored. This study is therefore aimed to investigate how the number of cells in the flow structure affects the wind effects acting on civil structures through Computational Fluid Dynamics (CFD) simulations. The paper is focused on the single-cell and dual-cell flow structure, both of which belong to the category of single-vortex tornadoes. For completeness, the wind characteristics of both types of tornadoes are also studied and compared. The applied CFD simulation strategies are verified based on a real-world tornado. The obtained results show that, due to the central downdraft in the dual-celled tornado, its turbulence intensity is higher than that of the single-celled tornado. The pressure profile for the dual-celled tornado has a wide, flat distribution, while the corresponding profile for the single-celled tornado has a narrow, single peak. The two drag forces induced by the single-celled tornado follow a typical trend, i.e., they reach their peak values when the dome center moves to the tornado core radius, while the corresponding variations under the dual-celled tornado tend to be more random. Similar observations can be found from the two overturning moments. This suggests that the wind loading induced by the dual-celled tornado is more dynamic than that induced by the single-celled tornado.