Simulation on the Stroke Protection Distance of Tall Buildings to Surrounding Buildings

Lightning is a kind of strong discharge phenomena in the atmosphere. It has a great impact on human living space especially cloud-to-ground lightning, making it widely concerned. Through a large number of lightning observation, the tip and the corner of tall buildings are usually striken rather than the relative low buildings and ground. The tall building can make surrounding atmospheric electric field produce a strong distortion effect, so that the tip and the corner of tall buildings trigger upward leader easier, connected with the downward leader. Numerous studies on single building attachment process are carried out, while in real urban environment, buildings are not isolated, and therefore, shielding effects between multiple buildings and the relationship between stroke protection distance of building and the related characteristic parameters of buildings are discussed.On the basis of the existing parameterization scheme of leader attachment process, a region near the ground is selected as study area, by changing spatial forms of lightning while keeping the other basic parameters constant. A series of lightning simulation experiment is conducted in the context of distribution of the same buildings. Results show that under the distribution of multiple buildings, the tall building is more intense in the environmental electric field distortion than the low building, upward leader is easier to be triggered. Meanwhile, the tall building has a shielding effect to the low building, and has a critical value of protection distance of the effect of low building, when the distance between tall building and low building is under the critical, the low building is safe from stroke, otherwise, the rate of low building being stroke has a upward trend. In addition, the result comes out that the critical value of protection distance and the height of tall building is positively correlated, and the height of low building is negatively correlated. Finally, the relationship between the critical value of protection distance and the building height is fitted, providing a reference value for lightning protection designing work.