HILBERT ENERGY SPECTRUM OF TURBULENCE AND ITS APPLICATION

抄録

Hilbert transform and empirical mode decomposition are summarized and applied to analyze the velocity signals of turbulence flow. Based on the Taylor’s frozen-turbulence hypothesis, the Hilbert spectra for turbulence flow are transferred to the forms in both wave-number space and physical space. A 10-minute sample of fluctuating wind velocity measured at 280m level of Beijing 325m meteorological tower is analyzed using both Hilbert-Huang transform and Fourier transform while the Hilbert spectra are contrasted with the Fourier spectra. The dissipation lengths of the three velocity components are computed respectively using Hilbert marginal spectra while the integral lengths are obtained through the correlation functions of intrinsic mode functions of each velocity component.