W. Top Changwatchai
Nicholas P. Chotiros
Appl. Res. Labs., Univ. of Texas at Austin, P.O. Box 8029, Austin, TX 78713-8029
The transmission of acoustic pulses from water into a water-saturated sandbed was observed in the 2- to 10-kHz band. An underwater spark source was used to transmit the pulses to a buried array of hydrophones, which varied in depth from 0 to 60 cm. The spark source was suspended 0.75 m above the sand and pulsed at 0.5-m horizontal intervals up to a distance of 3.5 m. Pulse compression processing was used to sharpen up the wave pulses and separate the direct pulse from reflected pulses, as well as to eliminate electrical interference from the spark generator. Speeds and attenuations of observed waves were computed from measurements. [Work supported by ONR.]