A PDF discretization scheme in wavenumber–frequency joint spectrum for simulating multivariate random fluctuating wind fields

Abstract

The wavenumber–frequency joint spectrum-based spectral representation method is an effective method for simulating multivariate random fluctuating wind fields. However, the simulation efficiency may not be quite satisfactory when the uniform discretizations in both frequency and wavenumber domains are employed. In this paper, a probability density function discretization scheme in wavenumber domain, which is actually an uneven discretization scheme, is proposed to alleviate the computational burden. In the proposed scheme, the wavenumber–frequency joint spectrum at a characteristic frequency is first taken as a probability density function. Then, the wavenumber domain is unevenly discretized according to the probability density function. Since the wavenumber–frequency joint spectrum may decay very fast in wavenumber domain, a uniform discretization is further applied in large intervals in wavenumber domain. Finally, the unevenly discrete wavenumbers and wavenumber intervals are substituted into the wavenumber–frequency joint spectrum-based spectral representation method for generating samples of multivariate random fluctuating wind fields, where the frequency domain is still uniformly discretized. The accuracy and efficiency of the proposed discretization scheme are compared with the uniform and conventional uneven discretization schemes. Practical applications of the proposed method are also investigated in various engineering scenarios.