In this study, we proposed a new method to calculate the fractal dimension by using a wavelet transform which is a time-frequency analysis method and try to evaluate the change of the similar structure in an unsteady signal. The procedure of our method is: 1) carrying out wavelet transform of the unsteady signal and obtaining the information about both time and frequency. 2) calculating the fractal dimension at each time from the wavelet transform of the unsteady signal. 3) evaluating change of the similar structure in the unsteady signal by using the fractal dimension obtained. Then the unsteady turbulence, such as jet flow and tumble flow in an engine were analyzed by using our approach. As a result, the change of the eddy structure can be shown very well.
|ジャーナル||Nippon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C|
|出版ステータス||Published - 1月 2002|
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