兰州大学机构库 >土木工程与力学学院
大气表面层中雷诺应力标度关系和涡结构
Alternative TitleScaling of wall-normal turbulence intensity and vertical eddy structures in the atmospheric surface layer
杨海博
Thesis Advisor薄天利
2018-04-05
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword高雷诺数壁湍流 大气表面层 涡结构 标度关系 雷诺应力 湍动能
Abstract

基于在中国甘肃省民勤地区建设的青土湖大气表面层观测阵列 Qingtu Lake Observation Array(QLOA)得到的大量优质近中性大气表面层三维风速数据,本论文分析了极高雷诺数下大气表面层对数区的雷诺应力标度关系和涡结构变化。整个实验测量区域几乎包含整个对数区(0.006δ 到 0.2δ,δ为大气表面层边界层厚度)。本文的主要发现是:垂向雷诺正应力(即垂向湍动能)随着高度的增大而出现显著的增加,这个结果与基于附着涡模型的经典标度关系和中低雷诺数情况存在着定性的差异,而且这种增加可以用线性关系来表征。流向、展向雷诺正应力在对数区中表现出对数线性关系,且存在明显的雷诺数效应。

本论文还分析了在流向-垂向平面涡结构的变化,并和中低雷诺数情况进行了对比。流向和展向速度脉动的涡结构是“attached”性质,在本论文的整个实验测量区间内是始终存在的。而垂向速度脉动的涡结构是“detached”性质,在靠近壁面的低处,几乎不存在或者存在较少的大涡结构,随着高度增加,这些结构逐渐增多且强度逐渐加强。此外,本论文对数据的不确定性和大气表面层各种因素对结果的影响进行了系统分析。

Other Abstract

Adequate high-quality data on three-dimensional velocities in the atmospheric surface layer (ASL) were acquired in the field at the Qingtu Lake Observation Array (QLOA). The measurement range occupies nearly the entire logarithmic layer from approximately 0.006δ to 0.2δ. The turbulence intensity and eddy structures of the velocity fluctuations in the logarithmic region were primarily analysed, and their variations in the z (wall-normal) direction were revealed. The primary finding was that the turbulent intensity of wall-normal velocity fluctuations exhibits a sharp upswing in the logarithmic region, which differs from classic scaling law and laboratory results. The upswing of the wall-normal turbulence intensity in the logarithmic region is deemed to be linear based on an ensemble of 20 sets of data. Streamwise and spanwise turbulence intensity in the logarithmic region both show logarithmic linear relationship and Reynolds number effect.

We analysed the wall-normal extent of the correlated structures and wall-normal spectra as well and the results were compared to low Reynolds number results in the laboratory. The vortes structures of streamwise and spanwise are “attached”, implying that they are always present in log region while vortes structures of wall-normal are “detached”, implying that there are almost absent or just a few of structures near the wall and as the heights increases, these structures gradually increase and become important. In addition, the uncertainty of the data and the influence of several factors on the results are also analysed.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226620
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
杨海博. 大气表面层中雷诺应力标度关系和涡结构[D]. 兰州. 兰州大学,2018.
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