| Autor: |
D'Luna, L. J., Newhouse, V. L. |
| Zdroj: |
Ultrasonic Imaging; July 1981, Vol. 3 Issue: 3 p271-293, 23p |
| Abstrakt: |
The detection of vortices is of potential interest in physiology (e.g. the detection of weak stenoses), and in fluid mechanics. In this paper a non-invasive method of detecting vortices in channel flows using pulsed RF Doppler ultrasound is described. A novel approach involving hybrid operation is taken in implementing a directional Doppler system. A scattering model of a vortex crossing an ultrasound beam is presented and theoretical simulations of the Doppler signals show good agreement with experiment. Experimental results showing the detection of both periodic and isolated vortices in channel flows are given. The Autoregressive or Maximum Entropy Method of spectral estimation is used to obtain the spectral estimates of the Doppler signals over short time intervals. It is shown that these spectral estimates can be used to estimate the velocity profiles of the detected vortices. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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