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Detection of Vortex Frequency in Gas Flow with Ultrasound

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Abstract:

The coincidence of vortices generated by a bluff body in a gaseous flow (Karman vortex street) with an ultrasonic beam crossing these vortices raises a lot of questions concerning physics and signal processing. The ultrasonic signal will be complex modulated. The spectrum of the resulted signal shows the carrier frequency of ultrasound and two narrow sidebands with the information about the modulation. For further signal processing the carrier frequency must be filtered. The carrier frequency can be shifted to zero by digital processing and undersampling the signal by an integer multiple. Then the sideband with its low frequency range can be analysed. The real and imaginary parts of the signal can be determined by sampling the signal shifted by 90 degrees (Hilbert transform). Even the 90 degree shifted angle can be measured by undersampling. The sensitivity of the vortex meter depends on the bluff body size. A simple relation between the bluff body dimension and the sensitivity, the vortex frequency, respectively, is shown.

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Periodical:

Key Engineering Materials (Volumes 295-296)

Pages:

515-520

DOI:

https://doi.org/10.4028/www.scientific.net/KEM.295-296.515

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Online since:

October 2005

Authors:

Volker Hans, C. Filips

Keywords:

Complex Modulation, Flow Measurement, Kalman Filter (KF), Undersampling

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© 2005 Trans Tech Publications Ltd. All Rights Reserved

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References

[1] A. Breier and H. Gatzmanga: tm-Technisches Messen, Vol. 62 (1998), p.22.

Google Scholar

[2] R.C. Baker: Flow Measurement Handbook (Cambridge University Press, 2000).

Google Scholar

[3] V. Hans and G. Poppen: Proc of FLOMEKO, Beijing, 1996, p.729.

Google Scholar

[4] V. Hans, G. Poppen, Ev. Lavante and S. Perpeet: Flow Measurement and Instrumentation, Vol. 9 (1998), p.79.

DOI: 10.1016/s0955-5986(98)00014-4

Google Scholar

[5] W. Bachmann: Signalanalyse (Vieweg-Verlag, Braunschweig, Wiesbaden 1992).

Google Scholar

[6] Ch. Filips and V. Hans: Proc of Systemics, Cybernetics and Information Conference, Orlando, Vol. 3 (2002), p.331.

Google Scholar

[7] M. Niemann: PhD Thesis (University of Essen, 2002).

Google Scholar

[8] M. Niemann and V. Hans: Proc of IEEE Instrumentation and Measurement Technology Conference, Anchorage, (2002).

Google Scholar

[9] V. Hans and H. Windorfer: Measurement, Vol. 33 (2003), p.121.

Google Scholar