Nonlinear Doppler effect and its use for bubble flow velocity measurement

Citation
In. Didenkulov et al., Nonlinear Doppler effect and its use for bubble flow velocity measurement, J ACOUST SO, 106(5), 1999, pp. 2431-2435
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary,"Optics & Acoustics
Journal title
JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA
ISSN journal
0001-4966 → ACNP
Volume
106
Issue
5
Year of publication
1999
Pages
2431 - 2435
Database
ISI
SICI code
0001-4966(199911)106:5<2431:NDEAIU>2.0.ZU;2-8
Abstract
The Doppler effect is a familiar phenomenon in linear acoustics. The nonlin ear Doppler effect is also possible when a moving target exhibits nonlinear responses. In: these cases Doppler frequency shifts arise at harmonics or combination frequencies in the scattered waves. For collinear geometry of p rimary beams, the nonlinear Doppler frequency shifts at the second harmonic and the combination frequencies are found to be the same as those for the linear scattering of those frequency components by the target. However, for highly, noncollinear primary beams, the difference frequency Doppler frequ ency shift can greatly exceed the linear one. This phenomenon is mainly stu died in the present work. Experimental verification done with flowing bubbl es in a tube shows good agreement with the theory. The suggested difference frequency Doppler technique can find applications in medical diagnostics o f blood flow as well as in industries and in oceanology. (C) 1999 Acoustica l Society of America. [S0001-4966(99)03709-1].