Wind-Tunnel Experiments of Turbulent Wind Fields over a Two-dimensional (2D) Steep Hill: Effects of the Stable Boundary Layer
Wind-Tunnel Experiments of Turbulent Wind Fields over a Two-dimensional (2D) Steep Hill: Effects of the Stable Boundary Layer
复制标题
二维 (2D) 陡山上湍流风场的风洞实验：稳定边界层的影响
DOI：
10.1007/s10546-023-00820-2
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发表时间：
2023
影响因子：
4.3
通讯作者：
Porté-Agel, Fernando
中科院分区：
文献类型：
--
作者：
Zhang, Wei;Markfort, Corey D.;Porté-Agel, Fernando
尽管利用了复杂的数值模型，但由陡峭地形引起的气流分离仍然是准确预测复杂地形上湍流边界层流动的一个重要障碍。大气热稳定性的增加，加上陡峭的地形，进一步复杂的破坏湍流风模式的确定。二维陡坡上热分层条件下的湍流分离流动在以往的实验研究中还没有得到广泛的解决。这种测量对于增强我们对流动物理的理解和验证数值模型至关重要。我们在热分层边界层风洞中测量了浸没在稳定边界层（体积Richardson数= 0.256）中的二维陡峭山丘上的湍流风流动。利用平面粒子图像测速技术对流动分离、回流区和流动再附着进行了表征。平均空气温度的垂直廓线及其波动也被量化的2D陡峭的山以上的代表性位置，并在近尾区。结果表明，分离的剪切层，开始附近的2D陡峭的山的顶部，占主导地位的物理过程，导致高湍流水平和湍流动能生产的尾区稳定和中性的热稳定性。虽然稳定的边界层并没有显着改变湍流模式周围的山，平均分离泡延长了13%，其垂直范围减少了约20%。此外，近尾流的湍流强度和湍流动能的降低归因于稳定边界层的相对低的湍流强度和低动量，由于浮力阻尼，与中性边界层相比。此外，一个明显的低温区-冷池-是超出了分离泡，反映了显着的掩护效果的二维陡峭的山的顺风流场和温度场。
Flow separation caused by steep topography remains a significant obstacle in accurately predicting turbulent boundary-layer flows over complex terrain, despite the utilization of sophisticated numerical models. The addition of atmospheric thermal stability, in conjunction with steep topography, further complicates the determination of disrupted turbulent wind patterns. The turbulent separated flows over a two-dimensional (2D) steep hill under thermal stratification has not been extensively addressed in previous experimental studies. Such measurements are crucial for enhancing our comprehension of flow physics and validating numerical models. We measured the turbulent wind flows over a 2D steep hill immersed in a stable boundary layer (of the bulk Richardson Number= 0.256) in a thermally-stratified boundary-layer wind tunnel. The flow separation, re-circulation zone and flow reattachment were characterized by the planar particle image velocimetry technique. Vertical profiles of mean air temperature and its fluctuations are also quantified at representative locations above the 2D steep hill and in the near wake region. Results indicate that the separated shear layer, initiated near the crest of the 2D steep hill, dominates the physical process leading to high turbulence levels and the turbulent kinetic energy production in the wake region for both stable and neutral thermal stability. Although the stable boundary layer does not dramatically change the turbulent flow pattern around the hill, the mean separation bubble is elongated by 13%, and its vertical extent is decreased by approximately 20%. Furthermore, the reduced turbulence intensities and turbulent kinetic energy of the near wake flow are attributed to the relatively low turbulence intensity and low momentum of the stable boundary layer due to buoyancy damping, compared to the neutral boundary layer. Additionally, a distinct low-temperature region—a cold pool—is extended beyond the separation bubble, reflecting the significant sheltering effect of the 2D steep hill on the downwind flow and temperature field.
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影响因子：
3.7
作者：
C. Hocut;D. Liberzon;H. Fernando
通讯作者：
C. Hocut;D. Liberzon;H. Fernando
具有不同坡度和接近流特性的二维山上气流分离和重新附着的粒子图像测速测量
影响因子：
4.3
作者：
I. Kanda;Yukio Yamao;K. Uehara;S. Wakamatsu
通讯作者：
S. Wakamatsu
影响因子：
3.1
作者：
Simpson, Colin C.;Sharples, Jason J.;McCabe, Matthew F.
通讯作者：
McCabe, Matthew F.
DOI：
10.1016/j.jweia.2007.01.002
发表时间：
2007-08
影响因子：
4.8
作者：
S. Cao;T. Tamura
通讯作者：
S. Cao;T. Tamura
影响因子：
4.3
作者：
J. Finnigan;K. Ayotte;I. Harman;G. Katul;H. Oldroyd;E. Patton;D. Poggi;A. Ross;P. Taylor
通讯作者：
J. Finnigan;K. Ayotte;I. Harman;G. Katul;H. Oldroyd;E. Patton;D. Poggi;A. Ross;P. Taylor