Characterization of an ultrasonic system using wavelet transforms

Moholkar, V.S. and Huitema, M. and Rekveld, S. and Warmoeskerken, M.M.C.G. (2002) Characterization of an ultrasonic system using wavelet transforms. Chemical Engineering Science, 57 (4). pp. 617-629. ISSN 0009-2509

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Abstract:	A new method has been developed for the determination of the spatial distribution of the cavitation intensity in an ultrasound processor. The method uses wavelet transform analysis of the acoustic emission profiles. The periodic modulation of the acoustic pressure field in an ultrasound processor causes unsteady radial motion of the bubbles, resulting in non-stationary acoustic emission profiles that cannot be analyzed by Fourier transform. The cavitation intensity has been judged experimentally and numerically. The experimental method used the “cavitation noise coefficient” defined as the sum of the energy at different scales (or levels) in the wavelet transform of the measured signal containing the subharmonic and harmonics of the fundamental frequency. The numerical method involved the simulation of the radial motion of a bubble and the pressure waves radiated by it, applying experimentally measured acoustic pressure signals as the forcing function. The numerically predicted spatial variation of the cavitation intensity was in agreement with the experimental measurements. It is proposed that the conical divergence of the acoustic waves from the transducers and the differences in the electrical and acoustical characteristics of the adjacent transducers in the bath give rise to a non-uniform cavitation intensity distribution.
Item Type:	Article
Copyright:	© 2002 Elsevier
Research Group:	Engineering of Fibrous Smart Materials (EFSM)
Link to this item:	http://purl.utwente.nl/publications/74784
Official URL:	http://dx.doi.org/10.1016/S0009-2509(01)00397-9
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