空间分辨率对建筑物尖端大气电场畸变影响的数值模拟研究

发布时间：2018-03-05 21:36

本文选题：大气电场畸变　切入点：空间分辨率　出处：《南京信息工程大学》2013年硕士论文　论文类型：学位论文

【摘要】：建筑物顶部的拐角和尖端对大气电场的畸变作用,是大气边界层中的众多放电现象重要的触发因子之一。较为精确的获取建筑物顶部的电场分布,对大气电学研究以及雷电防护工作均具有深远意义。但受观测手段的限制,数值仿真计算是此类研究的主要手段。使用离散网格代替连续空间的数值计算,因空间分辨率的引入,导致计算结果不可避免地产生系统误差。基于此,本文建立建筑物顶部大气电场计算的二维模型,通过大量不同分辨率下的敏感模拟实验,探讨建筑物尖端对大气电场畸变的影响；分析数值计算时系统误差的主要来源；并探索减小此误差的方法。本文的主要研究结果如下： (1)基于大量不同空间分辨率的模型输出结果,发现大气电场畸变系数与空间分辨率呈指数增加关系；并根据此关系,外推法估算出了连续空间下建筑物顶部的电场畸变系数大小,建立了此电场畸变系数与建筑物尺寸的多元回归方程。 (2)空间分辨率对大气电场畸变系数随建筑物及尖端的几何尺寸的变化关系式的函数形式不产生影响,但对关系式中各变量的系数产生较大影响。即无论是连续空间下还是离散空间下,建筑物顶部拐角处或者建筑物尖端顶部的大气电场畸变系数,皆与研究物体的高度呈线性增加关系,与研究物体的宽度呈指数递减关系；但对关系式中各变量的系数皆随空间分辨率的变细呈指数增加。 (3)使用离散空间代替连续空间,由空间分辨率不同而引入计算结果的系统误差,此误差值的大小仅与分辨率粗细有关,与建筑物尺寸的大小无关。当分辨率固定时,此误差值也是固定值,且分辨率越细,计算结果的系统误差越小。此外,使用外推法估算连续空间下的大气电场畸变系数,在建立拟合方程时,最细分辨率下的计算结果,对外推结果具有决定性作用。
[Abstract]:The distortion of the atmospheric electric field caused by the corner and tip of the top of the building is one of the important triggering factors of many discharge phenomena in the atmospheric boundary layer. It is of great significance for atmospheric electrical research and lightning protection. However, due to the limitation of observation means, numerical simulation is the main means of this kind of research. The discrete grid is used to replace the numerical calculation in continuous space. Because of the introduction of spatial resolution, the calculation result inevitably produces systematic error. Based on this, a two-dimensional model for calculating the atmospheric electric field at the top of a building is established, and a large number of sensitive simulation experiments at different resolutions are carried out. This paper discusses the influence of building tip on atmospheric electric field distortion, analyzes the main sources of systematic error in numerical calculation, and explores the methods to reduce this error. The main results of this paper are as follows:. 1) based on the output results of a large number of models with different spatial resolutions, it is found that the atmospheric electric field distortion coefficient increases exponentially with the spatial resolution, and according to this relationship, The extrapolation method estimates the magnitude of the electric field distortion coefficient at the top of the building in continuous space and establishes the multivariate regression equation between the electric field distortion coefficient and the building size. (2) the spatial resolution has no effect on the functional form of the relationship between the atmospheric electric field distortion coefficient and the geometric size of the building and its tip. But it has a great influence on the coefficients of the variables in the relationship, that is, the atmospheric electric field distortion coefficient at the top corner of the building or at the top of the building tip, whether in the continuous space or in the discrete space. All of them are linearly increased with the height of the studied object and exponentially decreasing with the width of the studied object, but the coefficients of each variable in the relationship increase exponentially with the change of spatial resolution. Using discrete space instead of continuous space, the systematic error of calculation result is introduced by different spatial resolution. The error value is only related to the resolution thickness, but independent of the size of the building. When the resolution is fixed, This error is also a fixed value, and the finer the resolution, the smaller the systematic error. In addition, the extrapolation method is used to estimate the atmospheric electric field distortion coefficient in continuous space. The result of extrapolation is decisive.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU119.2;TU856;P427.3

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