近地面脉动风速时程的分形模拟研究

Research on fractal simulation of subsurface fluctuating wind speed time-history

风荷载是不可忽略的结构设计参数,而风荷载大小是由风速决定的,所以风速时程的模拟非常重要。本文根据实测的近地面脉动风速时程,计算了其分形盒维数,进而采用具有分形特性的随机函数模拟了脉动风速时程。然后,提出了考虑空间相关性的脉动风速时程分形模拟方法,并将模拟结果与实测脉动风速进行了分形盒维数、概率分布、功率谱和互相关系数的对比,发现两者很相似。本文所提出的近地面脉动风速时程的分形模拟方法弥补了传统模拟方法的不足。

Wind load is a parameter that can not be overlooked in designing the structure. The scale of wind load is determined by the wind speed,so the simulation of wind speed is very important in determining the wind load. In this paper,according to the measurement of subsurface fluctuating wind speed time-history,the fractal box dimension is calculated and the stochastic function which is fractal has been adopted to simulate the subsurface fluctuating wind speed time-history at different heights. By comparing the experimental results with fractal box dimension,simulation results in the aspects of probability distribution,power spectrum in this paper,and cross correlation coefficient. It has found that they are very similar. So it is proved that the application of stochastic Weierstrass-Mandelbrot function simulation of the subsurface wind speed time-history is feasible.