Effect of protruding eave on the turbulence structures over two-dimensional semi-open street canyon
Effect of protruding eave on the turbulence structures over two-dimensional semi-open street canyon
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DOI：
10.1016/j.buildenv.2022.109921
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发表时间：
2022-12
影响因子：
7.4
通讯作者：
Abdillah Alwi;M. Mohamad;N. Ikegaya;A. Razak
中科院分区：
文献类型：
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作者：
Abdillah Alwi;M. Mohamad;N. Ikegaya;A. Razak
峡谷的半开放结构通常与屋檐、遮阳篷、阳台和拱廊等高架结构相关。尽管许多研究人员已经研究了这些结构对峡谷通风的影响，但对建筑层面具有突出屋檐的二维（2D）半开放街道峡谷流场的详细研究尚未得到充分研究。因此，在本研究中，进行了一系列大涡模拟（LES），以研究各种屋檐设计对二维半开放街道峡谷内部和上方的流动结构和湍流特性的影响。随着屋檐长度的增加以及屋檐在迎风侧或背风侧或两个建筑立面上的定位，随着流动的分离和冲击点的变化，涡流的大小会发生显着变化。湍流统计数据的空间分布描述了对屋檐尺寸和位置的强烈依赖性。由于屋檐的存在减弱了上述水流对街道峡谷的渗透，湍流强度和雷诺应力得到了系统性的降低。然而，空间平均剖面显示湍流统计明显依赖于屋檐的总长度，而不是单个屋檐的位置。平均风速的时空分布在所有情况下都呈现S形轮廓，而不是不同的屋檐配置。此外，喷射的发生频率在峡谷内占主导地位，而在建筑物高度上方的扫描则更大。
The semi-open configuration of canyons is often associated with elevated structures such as eaves, awnings, balconies and arcades. Although numerous researchers have investigated the influence of these structures on canyon ventilation, detail investigations on the flow fields over two-dimensional (2D) semi-open street canyon with protruding eaves at the building level have not been studied adequately. Therefore, in this study, a series of large eddy simulation (LES) was performed to investigate the effect of various eave designs on the modification of flow structure and turbulent characteristics within and above 2D semi-open street canyon. The size of the vortices changes significantly with increasing length of the eaves as well as with the positioning of the eaves on the windward or leeward side or on both building facades, as the detachment and impingement points of the flow change. Spatial distribution of the turbulence statistics depicts a strong dependency on the eave dimension and position. The turbulence intensities and Reynolds stress were systemically reduced as the presence of eaves attenuate the penetration of the above flow into the street canyon. However, spatially-averaged profiles showed a clear dependence of turbulence statistics on the total length of eaves instead of the position of individual eave. The spatio-temporal of the mean wind speed showed anS-shaped profile in all cases instead of the different eave configurations. Furthermore, the occurrence frequency of ejections was dominant within the canyon, while above the building height sweeps was greater.