Water Turbulence Detector.
Patent, Filed 17 Sep 71, patented 27 Aug 96,
DEPARTMENT OF THE NAVY WASHINGTON DC
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A Doppler shift flow meter array detects turbulence in the wake of a submarine. Three sets of transmitting and receiving sonic transducers are spaced in a line on a rigid support. The transmitting transducers emit ultrasonic energy which is reflected from particulate matter in a surrounding water medium. The reflected energy is detected by the receiving transducers. A digital Doppler meter associated with each set of transmitting and receiving transducers develops a digital count over a fixed interval that is equal to the Doppler shift between transmitted and received energy. First differences between adjacent pairs of digital Doppler meters are obtained by two digital subtractors, and the second difference between Doppler shifts is obtained by a third digital subtractor. The second difference is non-zero only when ocean turbulence is present, such as produced by a submarine.
- Acoustic Detection and Detectors