LAUSR

The present paper’s theory predicts phase velocity and attenuation for mud sediments that contain silt particles, and is based on the model of a suspension consisting of solid particles dispersed in a viscous liquid; the attenuation expression dates back to Lamb's Hydrodynamics and to Urick (JASA, 1948), clarified and rederived by Pierce, Siegmann, and Brown (POMA, 2017). The application to mud is based on the premise that silt particles are held in suspension by the loosely connected matrix of clay particles and that their natural oscillation frequencies are significantly less than the frequencies used in underwater acoustics. The present paper extends that theory with a fresh derivation based on concepts of matched asymptotic expansions and results in an expression for the complex wave number k as a function of the angular frequency. The results for phase velocity disagree with results published in the past by Ahuja (JASA, 1972) and Temkin (JASA, 2000). The assertion is made that the use of the theoreti...