基于分形理论的飞机雷击初始附着点的数值模拟

飞机雷击附着点的确定能够为飞机防雷设计提供依据,是飞机雷击区域划分和飞机各部件进行雷电试验鉴定的先决条件.本文提出了一种基于分形理论的飞机雷击初始附着点数值模拟的新方法.该方法首先依据标准SAE-ARP5416中有关飞机雷击附着点试验的规定,确定放电间隙、雷电起始坐标、飞机姿态和放电次数等参数,然后根据分形理论,使用电介质击穿模型模拟符合自然界雷电物理机理和几何特征的雷电先导分形发展过程,同时考虑飞机自身触发双向先导的情况,最终得到飞机的雷击附着点分布.通过本文方法仿真模拟得到飞机F-4雷击附着点的分布概率,并分别与该飞机飞行实验和实验室高压放电实验测试得到的真实雷击附着点的概率分布情况比较,结果基本吻合,验证了该方法的有效性.研究结果为飞机雷击附着点仿真模拟提供了一个有潜力的方法,可作为飞机防雷设计和今后开展相关研究工作的基础.

Numerical simulations of the lightning attachment points on airplane based on the fractal theory

Determination of the aircraft lightning attachment points which can provide the basis for the design of aircraft lightning protection, is a prerequisite for the division of lightning strike zones and the lightning test of aircraft components. In this paper, a novel numerical simulation method based on fractal theory is presented to simulate lightning attachment points on airplane. Firstly, the discharge gap distance, lightning starting coordinates, aircraft attitudes, discharge times and other parameters are determined according to the relevant provisions about aircraft lightning attachment point test in standard SAE-ARP5416. Then, according to the fractal theory, the dielectric breakdown model is used to simulate the fractal growth of the lightning leaders, which accords with physical mechanisms and geometric characteristics of nature lightning. Finally, considering the case where the aircraft itself triggers the bi-directional leader, we obtain the distribution of aircraft lightning attachment points. Because the probability distribution of lightning attachment points on aircraft F-4 obtained through the simulating is almost in line with those obtained through actual aircraft flight test and laboratory test, the proposed method is verified. The proposed method provides a potential way of simulating the lightning attachment points on aircraft. And this method can be used as the foundation of the aircraft lightning protection design and future related research work.