HYDROACOUSTIC VELOCIMETER SYSTEM.
AMERICAN ELECTRONIC LABS INC COLMAR PA
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The highly accurate acoustic velocimeter was designed to measure the velocity of sound in seawater, under laboratory conditions, at pressures up to 10,000 psi with an accuracy of one one-hundredth of one percent. This velocimeter is ultimately intended as a standard device for calibrating other velocimeters. The following techniques comprise the basis of this system 1 single-harmonic test signal method the phase-difference changes of a high-frequency test signal 25 Mc are observed and recorded while the distance between two transducers is changed by a known, precise amount and 2 Transient test signal method a transducer is shock excited by a very short electrical pulse, and the propagation time of the wavefront to a second transducer, a known distance from the first, is determined. Use of the two methods results in a selfchecking system. Agreement of the results of the two methods confirms the precision of the measurement.