Sediment acoustics modeling using in situ SAMS data
Abstract
The long-term objective is to address the impact of sediment inhomogeneity on sound propagation and reverberation from a few hundred hertz to 10 kHz. In this band, the frequency dependencies of sound speed and attenuation are important for applications, but cannot be inferred from high-frequency data, hence direct measurement is necessary. The Sediment Acoustic-speed Measurement System (SAMS) is designed to measure in situ sediment sound speed and attenuation within the surficial 3 m of sediments. SAMS has been successfully deployed in Shallow Water 2006 (SW06), Target and Reverberation Experiment 2013 (TREX13), and Seabed Characterization Experiment 2017 (SCE17). The main goal of this proposal is to obtain geoacoustic profiles in the SCE17 study area in the frequency range of 600 Hz~10 kHz. Toward that goal, a sediment acoustic simulator for SAMS will be built, which will assist extracting geoacoustic properties and detailed information pertaining to sediment structure, such as layering and gradients, by taking advantage of the multiple ray path geometry provided by the ten source/receiver pairs of SAMS. As a first step, preliminary sediment acoustic modeling work has been carried out using AMS data from TREX13 and compared to SAX99 in situ results for coarse sandy sites. With SAMS data taken in several different sediment types, physical mechanisms that control the frequency dependencies of sound speed and attenuation can be investigated through modeling, assuming bottom structures such as gradients and layering have been taken into account. In the case of fine-grained sediments as in SCE17, there is no accepted sediment acoustic model and therefore, in situ SAMS data are important for testing models that are currently under development.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 25, 2019
- Source ID
- N000141912257
Entities
People
- Jie Yang
Organizations
- Office of Naval Research
- United States Navy
- University of Washington