Numerical Simulation Of The Effects Of Spatial Resolution On Atmospheric Electric Field Distortion On Top Of The Building

Atmospheric electric field distortion, near the corner and the tip on the top of the building, is one of an important trigger factor of the discharge happened in the atmospheric boundary layer. It is meaningful to the atmospheric electricity researches and lightning protection programs that to achieve a more accurate value of the distortion. And because of the field observation’s limitation, numerical simulation has become a main method on the present studies. The value of the field distortion of a certain structure or the variation relationship between the values and the dimensions was computed by using discrete grids to replace continuous space. However, with different mesh spacing or resolutions, the calculations will be different. These differences are named as the systematic error which is one of an unavoidable factor that affects the accuracy in numerical simulation. Hence, in this paper,2D model about the electric distortion on top of the building was built for discussing the influence of building on its surrounding atmospheric electric field. Then by comparing the differences between several outputs of the model when using different resolutions, we analyzed the cause of these differences and explored the way to reduce them. The main conclusions are as follow:(1) Based on plenty of different spatial resolutions models outcomes, a significant exponential relationship has been found between the value of distortion coefficient and the resolution. And according to this relationship, extrapolation method is used in this paper to reckon the atmospheric electric field distortion factor about the point near the structure’s top corner in continuous spacing. And the non-linear regressive equation between the field distortion factor and structure’s dimension parameters was established.(2)The change of spatial resolutions doesn’t affect the form of variation law between atmospheric electric field distortion coefficient and tip’s height or width, no matter in continuous spacing or discrete space, the value of the distortion factor is linear increasing with the growth the structure’s height but exponential decreasing with the width widening. But it has a significant exponential impact on the value of distortion coefficient and the parameters of change law relationship equation.(3) The systematic error that caused by a certain resolution in numerical simulation is a fixed value, which just relates to the resolution and nothing about structure’s dimension. The higher resolution, the smaller error. Furthermore, a relative dependable distortion value in continuous spacing can be achieved from extrapolation by using the fit points which value must close to the value in continuous spacing.