Numerical Simulation Of Lightning Attachment Process Based On Electric Field Distortion At Pointed End

Cloud-to-Ground lightning processes have a great impact on our production activities.Further, lightning attachment processes have an important impact on cloud-to-ground lightning. Thus, study on lightning attachment process is particularly significant. The lightning observation is developing. However, the field observation has limitations.So, researching characteristics of lightning attachment process by numerical simulation have a specific significance. The study result is not only beneficial to improve the theoretical research for lightning attachment process, but also beneficial to understand deeper how to adopt the lightning protection measures for buildings. In this paper, firstly we discuss the related research on the electric field calculation. Then based on the electric field calculation, we establish a set of lightning development mode near ground. Finally, we research lightning attachment process by established mode. The main conclusions of each part are given as following.The study result about effects of shape of buildings on electric field distortion found:There is a complicated relation between β(maximum distort coefficient of electric field) and the width of the building. When the degree of bending is greater than or equal to 1,β is exponentially decreasing with the increase of width.When the degree of bending is less than 1,β is linearly decreasing with the increase of width.β is decreasing with the increase of the degree of bending. Also, the relation between β and the height of the building is not only linear relation.Based on the established mode, we discussed characteristics of the cloud-to-ground lightning via simulating different lightning types by changing random parameter. The simulation results showed:The stroke point、the length of upward leader、striking distance、the range of the horizontal and the tip location of downward leader when upward leader trigger will change with the lightning spatial form change. In addition, according to a series of statistical outcomes, the length of downward leader and the length of upward leader near the ground have certain linear correlation.Finally, we study the lightning attachment process via simulating different lightning types by changing random parameter. The simulation results showed there are five different forms of lightning attachment process totally. There is the connection of the tip of downward leader to the tip of upward leader、the connection of the main branch of downward leader to the tip of upward leader、the connection of the tip of downward leader to the main branch of upward leader、the upward leader triggered is not connect with downward leader and the connection of the tip of downward leader to the tip of upward leader which triggered from ground. The discuss about difference between lightning factors on different lightning attachment process forms found that the length of leader have certain differences due to lightning attachment process form is different.