Published: CABEQ 27 (3) (2013) 251–257
Paper type: Original Scientific Paper
H. Meng, F. Wang, Y. Yu, W. Wang and J. Wu
In order to quantitatively evaluate the multiscale corrections of instantaneous flow in the novel circulating jet tank, the instantaneous pressure fluctuation signals (PFS) are measured by a data acquisition system. The original PFS are decomposed into seven uniform frequency bands from 0 to 70 Hz and a much wider frequency band from 70 to 250 Hz. The linear and nonlinear correlation characteristics of PFS under different circumferential angles and frequency bands are evaluated with autocorrelation and mutual information functions, respectively. With the increasing time delays, the autocorrelation of the original PFS decreases quickly and then fluctuates near zero. The fluctuations amplitudes, linear and nonlinear correlations decrease as the lower limits of decomposition frequency bands increase. The experimental results indicate that the signals of more than 50 Hz in frequency have no linear correlation, and there are no nonlinear and linear correlations for the time series signals, which are over 60 Hz in frequency.
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Circulating jet tank, mutual information function, autocorrelation, pressure fluctuation