Analysis of Turbulent Characteristics of Unevenly Velocity Signals in KSM Used Empirical Mode Decomposition and Lomb Periodogram

In this paper, Lomb periodogram estimate as a new spectrum calculation approach was used to deal with unevenly sampled signals sampled by Laser Doppler Particle Analyzer in Kenics Static Mixer. The effectiveness of the method was demonstrated by the simulations of deterministic model. The time series of instantaneous velocity in the turbulent region under the range of Re between 3972 and 11916 were firstly decomposed by empirical mode decomposition, and intrinsic mode functions were obtained. After that, the spectrum analyses of intrinsic mode function were evaluated based on Lomb periodogram estimate. The power spectra distribution shows that the energy of instantaneous velocity signal in KSM concentrates within 10Hz, and high frequency signal contains low energy.