基于近地观测的台风阵风因子研究

发布时间：2018-07-24 13:30

【摘要】：我国东南沿海常年受到台风侵袭，台风的强致灾性给该地区造成巨大经济财产损失的同时也对建筑结构的抗风安全性提出了更高要求。阵风因子表征了自然风的脉动强弱，是建筑结构抗风设计的重要参量。本文基于台风场实测资料对阵风因子的取值及其影响因素展开了系统研究，，主要内容可概括为以下三个方面：搭建了一套可移动式台风近地层风场特性实测网络。该网络由8个2.5米高的近地测风塔构成，具有安置灵活、使用高效的特点，可实现台风近地层风场的空间多点同步观测。利用该实测网络开展了一次近地常态风观测实验，对实测资料进行了风场特征分析，主要包括湍流积分尺度、脉动风速谱、相关系数、相干函数等。从脉动风的空间相关性出发，提出了一种考虑平均风速和结构尺寸效应的阵风因子确定方法。首先基于滑动平均滤波与气动导纳等效原则建立了阵风时距的合理确定方法，并通过对比分析5种常用的气动导纳函数，获得了等效阵风时距计算公式。然后针对实测脉动风较强的非高斯特征，推导了非高斯过程（包含硬化高斯过程和软化高斯过程）的阵风因子理论模型，并利用实测数据对该模型准确性进行了检验。最后将上述阵风因子理论模型用于实测阵风因子修正，利用2006-2008年间影响我国的三次台风过程实测资料，给出了A、B两类场地经修正后的阵风因子曲线，从而建立了合理确定阵风因子的完整流程。为探究实测台风场中部分较大阵风因子值的合理性及其形成机理，从375个台风场实测样本中选取了8个阵风因子值异常偏大的非常态样本以及1个极端异常样本进行了系统研究。首先针对样本所处台风风场位置、样本的非高斯特性和非平稳特性等表观因素进行了初步分析；然后借助小波变换的多尺度分析方法着重研究了湍流间歇性的影响，比较了相干结构提取前后样本各尺度间歇性、能量分布、非平稳性、非高斯性以及实测阵风因子值的变化情况，最终分析认为非高斯与非平稳性是引起非常态阵风因子的直接原因，而多尺度相干结构造成的湍流间歇性为其本质根源。
[Abstract]:The southeast coast of China has been hit by typhoons all the year round. The strong disaster caused by typhoons has caused huge economic and property losses in this area, but also put forward higher requirements for the safety of building structures against wind. The gust factor is an important parameter in the wind resistant design of building structures, which indicates the intensity of the natural wind pulsation. Based on the measured data of typhoon field, this paper makes a systematic study on the values of gust factors and their influencing factors. The main contents can be summarized as follows: a set of observational network of wind field characteristics of movable typhoon near the ground is set up. The network is composed of 8 near-earth wind towers with a height of 2.5 meters. It has the characteristics of flexible placement and efficient use. It can realize the spatial multi-point synchronous observation of typhoon wind field near the ground. In this paper, a near-earth normal wind observation experiment is carried out using this network, and the wind field characteristics of the measured data are analyzed, including turbulence integral scale, fluctuating wind velocity spectrum, correlation coefficient, coherence function and so on. Based on the spatial correlation of pulsating wind, a method for determining gust factors considering the effect of mean wind speed and structure size is proposed. Based on the principle of moving average filter and equivalent aerodynamic admittance, a reasonable method for determining the time interval of gust is established, and by comparing and analyzing five kinds of commonly used pneumatic admittance functions, the formula for calculating the equivalent gust time distance is obtained. Based on the non-Gao Si characteristics of the measured pulsating wind, a theoretical model of gust factor for non-Gao Si processes (including hardening Gao Si process and softening Gao Si process) is derived, and the accuracy of the model is verified by using the measured data. Finally, the theoretical model of gust factors is applied to the correction of measured gust factors. Using the measured data of three typhoons affecting China from 2006 to 2008, the modified gust factor curves of two kinds of sites are given. Thus the complete process of reasonably determining the gust factor is established. In order to explore the rationality and formation mechanism of some larger gust factor values in typhoon field, Eight abnormal samples with abnormal gust factor values and one extreme anomaly sample were selected from 375 typhoon field samples for systematic study. In this paper, the position of typhoon wind field, the non-Gao Si characteristic and non-stationary characteristic of the sample are analyzed, and the effects of turbulence intermittence are studied with the help of the wavelet transform multi-scale analysis method. The variation of intermittent, energy distribution, nonstationary, non-Gao Si and measured gust factor values of samples before and after coherent structure extraction are compared. It is concluded that non-Gao Si and non-stationarity are the direct causes of the unnormal gust factors, and the turbulence intermittency caused by multi-scale coherent structures is the essential source.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU352.2

【相似文献】