Simulation of Fluctuating Wind Speed Fields by Stochastic Harmonic Function Representation Method Based on Joint Wavenumber-Frequency Power Spectrum

Abstract

Simulation of wind speed fields usually plays a crucial role in the reliability analysis of large-size and high-rise structures such as tall buildings, long-span bridges and offshore wind turbines. To simulate a fluctuating wind speed field by the spectral representation method (SRM), two schemes can be adopted: (1) the conventional SRM, involving the decomposition of the cross power spectrum density (XPSD) matrix of fluctuating wind speed inevitably

and (2) the joint wavenumber-frequency spectrum based SRM, where a series of trigonometric functions are directly superimposed without any decompositions of XPSD matrix. However, both the two approaches involve large amounts of random variables, which hinder the reliability analysis of structures. In this paper, the stochastic harmonic function (SHF) representation method is extended and integrated with the joint wavenumber-frequency power spectrum to simulate fluctuating wind speed fields in one spatial dimension. Further, an efficient non-uniformly discretized scheme in wavenumber and frequency directions is suggested such that the number of random variables is dramatically reduced. Simulation results demonstrate the efficiency and validity of the proposed method.