热带气旋风场特性及其对低矮房屋屋面风压影响的实测研究

发布时间：2018-02-03 14:03

本文关键词： 低矮房屋现场实测热带气旋阵风因子脉动风速谱竖向风攻角屋面风压　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：灾后调查显示,风灾中损毁的建筑物多数为低矮房屋。因此,深入了解该类建筑风致破坏的机理具有重要意义。由于建筑物所受风荷载主要由来流风特性决定,所以了解来流风特性是研究建筑物风载特性的前提。本文利用实测的风速风向和双坡屋盖表面风压数据,首先对阵风因子和脉动风速谱这两个重要的湍流参数进行了研究,然后探讨了来流竖向风攻角对双坡低矮房屋屋面风压的影响。基于在10次热带气旋中采集的高分辨率风速数据,研究了热带气旋中阵风因子的特性。结果表明,阵风因子与地面粗糙长度之间存在明显的非线性关系。为了减弱地貌对阵风因子统计结果的影响,根据地面粗糙长度值将地貌分成了四类。在同种地貌中,当平均风速大于10m/s时,顺风向阵风因子平均值基本不随平均风速的增大而变化。以10min为参考时距,海面地貌、平滑地貌、开阔地貌和较粗糙开阔地貌中,3s时距阵风因子实测平均值分别为1.26、1.35、1.52和1.65,1min时距阵风因子实测平均值分别为1.11、1.15、1.18和1.27。海面地貌中顺风向3s阵风因子分布接近高斯分布,平滑地貌中顺风向3s阵风因子分布呈轻微左偏,开阔地貌和较粗糙开阔地貌中顺风向3s阵风因子呈右偏。另外,对阵风因子与脉动风向和湍流强度的关系进行了研究,结果表明阵风因子与脉动风向呈明显的线性关系,与湍流强度呈正相关。从多个热带气旋的风速数据中选取了96个时长为1小时的样本用于脉动风速谱特性的分析,采用EMD法对含有非线性趋势项的风速样本进行了处理,显示了良好的效果。实测脉动风速谱与经验谱的对比表明Karman谱在低频段和惯性子区都与实测谱吻合的很好。Davenport谱可以比较准确地估计脉动风速谱峰值的位置和大小,在惯性子区范围内,能够较好的吻合实测谱,但其严重低估了低频段的谱值;Kaimal谱在低频段与实测谱吻合较好,惯性子区内,略高与实测谱值。另外,热带气旋眼壁区三个风速分量上的脉动风速谱,在惯性子区内均明显高于外围大风区的脉动风速谱,同时,其低频段低于外围大风区的脉动风速谱。无论是热带气旋眼壁区域还是在其外围大风区,三向脉动风速谱在惯性子区范围内均能较好的吻合Kolmogorov-5 3幂次律。基于在热带风暴“彩虹”和“苏迪罗”中同步采集的风速风向以及屋面风压数据,分析了来流竖向风攻角对双坡低矮建筑屋面风压的影响。结果表明屋面风压与来流竖向攻角之间呈线性正相关关系。来流垂直于屋脊线时,屋盖迎风前缘区域受来流竖向风攻角的影响最为严重,距离迎风前缘越远的屋面区域受来流竖向攻角的影响越小。但屋盖背风面距离屋脊较近的区域受来流竖向攻角的影响程度会有一定程度的增强。斜风向下,屋面端部区域风压同样会受来流竖向攻角的影响。由于风洞试验中未模拟竖向攻角的影响,所以来流竖向攻角可能是造成风洞试验和实测结果在迎风前缘和屋脊附近区域存在差异的原因之一。
[Abstract]:Post disaster survey shows that the majority of buildings damaged in hurricane low rise buildings. Therefore, to deeply understand the failure mechanism of this kind of building style is of great significance. Because of the wind characteristics of the wind load of buildings mainly flow, so the understanding of wind characteristics is the premise of wind load characteristics of buildings. By using the measured wind speed and wind direction and double slope roof surface pressure data, the gust factor and wind spectrum of these two important parameters of turbulence are studied, and then discusses the influence of flow vertical wind attack angle on the double slope of low rise buildings roof pressure. High resolution wind speed data acquisition in the 10 Tropical Cyclone Based on the characteristics of the gust factor in tropical cyclones. The results showed that the obvious nonlinear relationship between gust factor and surface roughness. In order to reduce the influence of landform statistical results of gust factor, root According to the surface roughness value will be divided into four categories. The landform in the same landform, when the average wind speed is greater than 10m/s, the average value of along wind gust factor variation increased with the average wind speed. With 10min as the reference distance, sea surface topography, landform and geomorphology is smooth, wide open rough landforms, 3S from the gust factor measured average values were 1.26,1.35,1.52 and 1.65,1min from the gust factor measured average values were 1.11,1.15,1.18 and 1.27. in sea landform wind 3S gust factor distribution is close to the Gauss distribution, wind gust factor 3S in smooth topography distribution was slightly skewed to the left, open landform and rough open landform wind gust factor was 3S in the right side. In addition, the relationship between the fluctuating wind and gust factor and turbulence intensity were studied. The results show that the gust factor showed a linear relationship with the fluctuating wind and turbulence intensity is. Positive correlation. The wind speed data from a plurality of tropical cyclones from analysis of pulsating wind spectrum characteristics of the long 1 hour sample for 96 hours, the EMD method is used to deal with nonlinear trend wind samples, showed good results. The measured wind spectrum compared with the spectra show that the Karman spectrum of experience good.Davenport at low frequency and inertial subrange are consistent with the measured spectral spectrum can accurately estimate wind spectrum peak position and size in the inertial subrange, can fit the measured spectrum better, but it seriously underestimated the frequency spectrum; Kaimal spectrum at low frequency and spectrum good agreement within the inertial subrange, spectrum value is slightly higher with the measured wind speed of tropical cyclones. In addition, the eye wall region and three velocity components of the spectrum, at the same time in the inertial subrange in fluctuating wind speed were significantly higher than that of the external wind zone, the low frequency spectrum. Below the external wind area fluctuating wind spectrum. Both the tropical cyclone eye wall region or in its periphery area to the three winds, wind spectrum within the inertial subrange can fit Kolmogorov-5 better 3 power-law. Based on the tropical storm "Rainbow" and "SOUDELOR" synchronous acquisition of wind and the wind pressure data, analyzed the influence of flow vertical wind attack angle on the double slope on the roof of low pressure. The results show that the wind pressure and flow between the vertical angle of attack increases linearly. The flow perpendicular to the ridge line, the front edge of the area affected by the roof effect to vertical wind flow angle of attack was the most serious, affecting the roof the distance between the front edge region by the flow of vertical angle of attack is small. But the distance is near the leeward roof roof area affected by the degree of vertical flow angle of attack will enhanced to a certain extent. Oblique wind down the roof The wind pressure at the end area is also affected by the vertical attack angle of incoming current. Because the influence of vertical attack angle is not simulated in wind tunnel test, the vertical attack angle of incoming flow may be one of the reasons for the difference between wind tunnel test and measured results in the vicinity of windward front and roof.

【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU312.1

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