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Multifractal characteristics of intermittent turbulence in the urban canopy layer

期刊名称：ATMOSPHERIC AND OCEANIC SCIENCE LETTERS
时间：2015.1.1
页码：72-77
分类：P315.5[天文地球—地震学;天文地球—固体地球物理学;天文地球—地球物理学] TP391.41[自动化与计算机技术—计算机应用技术;自动化与计算机技术—计算机科学与技术]
作者机构：[1]International Center for Climate and Environment Science (ICCES), Institute of Atmospheric Physics, Chinese Academy of Science, B eijing 100029, China, [2]State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC), Institute of Atmospheric Phys- ics, Chinese Academy of Sciences, Beijing 100029, China
相关基金：This research was supported by the National Natural Science Foundation of China （Grant Nos. 11472272 and 91215302） and the Special Fund for Meteorological Research in the Public Interest （Grant No. GYHY201206041）.
相关项目：重大建筑与桥梁强/台风灾变的集成研究

关键词：多重分形, 分形特征, 间歇性, 冠层, 城市, 奇异指数, 高时间分辨率, 湍流耗散, urban canopy layer, intermittent turbulence,turbulent dissipation, multifractality, singularity spectrum

中文摘要：

精力和充分发达的断断续续的骚乱的热驱散的 multifractality 被奇特光谱为描绘 multifractals 的奇特的集合的分数维的尺寸在不稳定的条件下面在城市的华盖层调查。以便在惯性的范围获得小规模的狂暴的驱散的高顺序的时刻性质，有 100 Hz 的高采样频率的一张超声的风速表被使用。作者发现狂暴的信号能到处是单个的。而且，精力的单个代表和热驱散率最经常在约 0.2 点被遇到，它是比为在一个中等雷纳兹数字的一条风隧道的单个代表显著地小的。证据在一个高级雷纳兹数字在城市的华盖层显示骚乱的更高的 intermittency，它被数据与高时间的分辨率表明。而且，温度地比速度地更断断续续。另外，大量样品能被用于结果的确认。

英文摘要：

The multifractality of energy and thermal dis- sipation of fully developed intermittent turbulence is in- vestigated in the urban canopy layer under unstable con- ditions by the singularity spectrum for the fractal dimen- sions of sets of singularities characterizing multifractals. In order to obtain high-order moment properties of small- scale turbulent dissipation in the inertial range, an ultra- sonic anemometer with a high sampling frequency of 100 Hz was used. The authors found that the turbulent signal could be singular everywhere. Moreover, the singular exponents of energy and thermal dissipation rates are most frequently encountered at around 0.2, which is sig- nificantly smaller than the singular exponents for a wind tunnel at a moderate Reynolds number. The evidence in- dicates a higher intermittency of turbulence in the urban canopy layer at a high Reynolds number, which is dem- onstrated by the data with high temporal resolution. Fur- thermore, the temperature field is more intermittent than the velocity field. In addition, a large amount of samples could be used for verification of the results.