Evaluation of sound velocity inside underwater acoustic materials using test panel acoustic measurements

Evaluation of underwater acoustic propagation model (Ray theory) in a river using Fluvial Acoustic Tomography System

Underwater acoustics is widely used in many applications, such as oceanography, marine biology, hydrography, fishery, etc. Different models are introduced to simulate the underwater acoustic propagation in the oceans and the seas. In this study, the Ray Theory model is used to simulate the acoustic wave propagation in a shallow-freshwater river (Gono River) located in western part of Japan. The...

Effect of porosity on the characteristics of underwater acoustic sound absorbers using theoretical models‎

Porous materials have good acoustic damping characteristics over a wide frequency range. As for sound waves, many small-scale pores in the coating materials can convert underwater-coating to rough surfaces. The main property of porous absorbents is their resistance against incident sound wave that leads to damping effect. From a physical point of view, damping occurs due to friction between flu...

Piezoelectric Materials Used in Underwater Acoustic Transducers

Target Localization in Underwater Acoustic Sensor Networks Using RSS Measurements

This paper addresses the target localization problems based on received signal strength (RSS) measurements in underwater acoustic wireless sensor network (UWSN). Firstly, the problems based on the maximum likelihood (ML) criterion for estimating target localization in cases of both known and unknown transmit power are respectively derived, and fast implementation algorithms are proposed by tran...

Investigation on acoustic behavior of acoustic porous absorbers to ‎absorb sound energy and transmission loss index

In this study, the acoustic properties of porous absorbents with different porosity levels have been evaluated using different mathematical models. These models use one or more parameters of materials for calculating acoustic characteristics. In all of these models, materials are considered as equivalent fluid and reactionary characteristics have not been taken into account.