The Analysis Of The Characteristic Scale And The Research Of The Circular Cylinders In Nonlinear Dynamics

The disturbance noise is always existence in data acquisition, which would be confused with the usable signal and influence the analysis and the research. We propose the pretreatment of the signal before the time-frequency analysis and frequency analysis in this paper. Over the applications of the EMD-based, we reduced the noise by self-adapted filtering. Compared with the wavelet packets, the EMD-based method has more accurate analysis in local region. The tradition signal processing method would also lose the usable signal in the same frequency region when removing the disturbing signal. We propose to remove the disturbing signal in the energy characteristic scale, which could keep the usable signal. Because of the existence of the different energy-scale in the flow distribution, we also propose to polish the large-scale eddies. Since the EMD method proposes the signal based on the self-characteristic-scale of the signal, we polish eddies in the EMD method, which could help us to analyze the movement regular of the large eddies.The experiment is an important method to research the circular cylinders. In order to find more valuable information to reveal the mechanism of the flow, we process the gas-solid synchronization signals by time-frequency analysis and frequency analysis method. We also analyze and describe the regular of eddies changing in the flow distribution from the energy characteristic scale.The tradition numerical simulation researches the circular cylinders from the time analysis, which could show us the directly phenomenon. In this paper, we advanced the three-dimensional numerical simulation, based on the LES method of Fluent. We measured the gas fluctuating velocity and the solid fluctuating pressure by means of setting up the surface point. The simulation data would be also processed by time-frequency analysis and frequency analysis method. By comparing the experimental result and the simulation result, we could find the flow regular in different region, pick up the usable signal and grasp the regular of eddies changing.