In propeller cavitation pulsation pressure testing,the stability of cavitation significantly affects the time domain char-acteristics of the induced pulsation pressure.This stability also determines the accuracy of predicted cavitation pulsation pres-sure.Three processing methods are compared:ordinary FFT(Fast Fourier Transform);averaging the signal in the time do-main before Fourier transform(Time-domain averaged FFT);averaging the signal in the frequency domain after Fourier trans-form(Frequency-domain averaged FFT).The calculations were conducted to analyze the pulse pressure signals induced by sta-ble and unstable vacuoles.The results indicate that the Time-domain averaged FFT and the Frequency-domain averaged FFT can eliminate the interference of random factors and produce consistent prediction results when compared to the direct FFT method.However,the Time-domain averaged FFT method is not applicable for unstable cavitation.In that case,the Frequen-cy-domain averaged FFT method can more accurately predict the pulse pressure amplitude.
维普
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