Study on the frequency dependence of the sound speed and attenuation in muddy sediments in shallow water
Abstract
While there have been numerous theoretical and experimental studies on the properties of marine granular sands, there are significa""ntly fewer studies on sediments classified as muds. With regard to models, the heuristic model proposed by Biot needs to be defined"" anew for mud. As for the experimental measurements of the sound attenuation in mud, the data analysis results published in limited"" papers show large disparities. Therefore, convincing experimental databases of the sound speed and attenuation in mud are desirable" to test the validity of the geoacoustic models for muddy sediments. The ONR-sponsored Seabed Characterization Experiment (SBCE) was" conducted in the New England Mud Patch in the spring of 2017. Here, broadband signals (e.g. SUS charges and combustive sound source" signals) measured during SBCE are proposed for the study on the frequency dependence of mud properties. One can extract the acousti"c normal mode characteristics including modal dispersion curve with the Airy phase structure, modal amplitude, modal attenuation coe""fficient, and mode depth function from the SBCE 2017 data. These normal mode characteristics will be utilized in geoacoustic inversi"on algorithms to determine the frequency dependence of geoaoustic parameters in muddy sediments. The performance of different inversion methods using different normal mode characteristics can then be evaluated in terms of their inverted results. The performance as"sessment will help to choose appropriate objective functions at certain ranges, depths, azimuths, and frequency bands of interest.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 26, 2018
- Source ID
- N000141812168
Entities
People
- Lin Wan
Organizations
- Office of Naval Research
- United States Navy
- University of Delaware