基于多元EMD-AM/FM分解的多点非平稳雷暴风速模拟

SIMULATION OF MULTIVARIATE NON-STATIONARY THUNDERSTORM BASED ON MEMD-AM/FM DECOMPOSITION

雷暴风对建筑物和输电线塔等结构具有很大的破坏性。为了准确估算结构的动力响应,获得可靠的风速样本至关重要。该文结合多元经验模态分解(MEMD),调频函数/调幅函数(AM/FM)分解和本征正交分解(POD)建立了基于时频分析的非平稳多点风速的模拟方法。第一,采用MEMD分解多点风速,产生固有模态函数;第二,采用AM/FM分解计算各点的固有模态函数的瞬时频率和瞬时幅值;第三,利用POD对瞬时频率解耦;第四,将瞬时幅值和解耦后的瞬时频率用于重构多点非平稳风速。实测多点雷暴风的模拟结果表明:MEMD-AM/FM分解-POD方法能满意地模拟多点非平稳雷暴风速。

Extreme wind like thunderstorm has a destructive effect on structures adopted by buildings and transmission towers.In order to analyze the dynamic response of a structure,it is essential to obtain reliable wind samples.Thusly,a time-frequency analysis-based method,composed of multivariate empirical mode decomposition(MEMD),amplitude modulation/frequency modulation(AM/FM)decomposition and proper orthogonal decomposition(POD),is proposed to simulate multivariate non-stationary wind speed.Firstly,MEMD decomposes multivariate non-stationary wind speed into a set of intrinsic mode functions.Secondly,AM/FM decomposition calculates the instantaneous frequency and instantaneous amplitude of each intrinsic mode function.Thirdly,the instantaneous frequency is decoupled by POD.Finally,the instantaneous amplitude and decoupled instantaneous frequency is used to reconstruct multivariate non-stationary wind speed.The simulation results of measured thunderstorm wind datas shows that MEMD-AM/FM decomposition-POD serves as a powerful tool in the simulation of multivariate non-stationary thunderstorm wind speed.