Abstract
Measurements of the sound speed characteristic of the high porosity Dodge Pond mud were found to have a sonic speed less than that observed by Wood and Weston [Acustica 14, (1964)], a compressional speed 3% less than that of water. Other experiments performed on muddy sediments at frequencies greater than 1 kHz are consistent with the Dodge Pond observations when microbubbles are present. The presence of bubbles is known to be an important factor in decreasing the sound speed. A theoretical treatment of “muddy sediments,” the card house theory [Pierce and Carey, POMA 5, 7001, (2009)], estimated the slow sound speed and frequency dispersion proportional to mud porosity, Cmud ≈ (0.91–0.97)Cw. The presence of microbubbles can lower the sound speed consistent with the Mallock–Wood equation when the bubble size distribution and mean bubble separation are less than the wavelength of the propagating wave. Since measurement of the bubble size distribution within the mud is difficult; theoretical limits on the size distribution in the complex card house structure can be useful in interpreting measurements on muddy sediments and provide a basis for acoustic distribution measurement. [Work supported by the ONR OA and the NSWC PCD.]
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
