The effect of a layer of varying density on high-frequency acoustic reflection, forward propagation loss and backscattering strength
Abstract
This report examines the impact that a thin layer of varying density would have on high-frequency reflection, forward loss and backscattering of acoustic plane waves from the seafloor. A functional form for density stratification was found by examination of several high-resolution density profiles obtained from x-ray computed tomography scans of seafloor cores. A solution based on these general profiles was used to estimate the reflection coefficient. The influence of the density profile on reflection loss and backscatter was then calculated using the estimated reflection coefficient. Parameter values used in simulations were obtained from the literature or from the CT scans of cores. It was found that inclusion of a density profile adds a strong frequency dependence to estimates of the reflection coefficient and forward loss. The largest effect on total scattering strength is near normal incidence where returns are dominated by interface scattering. The effect of the density profile on the strength of acoustic returns suggests that care should be taken when using high-frequency systems for measuring sediment properties, especially near normal incidence.
Report Number
SR-262Date
1997/06Author(s)
Lyons, Anthony P.
; Orsi, T.H.
Related items
Showing items related by title, author, creator and subject.
-
Performance assessment of propagation models in AESS-6.0
Ferla, Carlo M.; Jensen, Finn B. (NATO. SACLANTCEN, 1999/08)A set of AESS propagation-loss predictions has been generated for typical operational scenarios in both deep and shallow water, for two sonar frequencies (500 and 3500 Hz) and for several source-receiver combinations. ... -
PC-based propagation and sonar prediction models
Dreini, Giancarlo; Isoppo, Cinzia; Jensen, Finn B. (NATO. SACLANTCEN, 1995/12)Six acoustic models available for use on PC's are tested on a series of typical propagation situations from the North Atlantic and the Mediterranean. The model set includes both early US Navy models (ASTRAL, FACT, RAYMODE) ... -
Review of numerical models in underwater acoustics including recently developed fast-field program
Jensen, Finn B.; Schmidt, Henrik (NATO. SACLANTCEN, 1984/12)Two papers given by SACLANTCEN personnel at the NATO Advanced Research Workshop on Hybrid Formulation of Wave Propagation and Scattering at Castel Gandolfo, Rome, Italy on 30 August to 3 September 1983 are published as a ...