For shallow-water waveguides and mid-frequency broadband acoustic signals, ocean acoustic tomography (OAT) is based on the multi-path aspect of wave propagation. Using arrays in emission and reception and advanced array processing, every acoustic arrival can be isolated and matched to an eigenray that is defined not only by its travel time but also by its launch and reception angles. Classicall...

In order to study the possibility of acoustic detection of ultra-high energy neutrinos in water, our group is planning to deploy and operate an array of acoustic sensors using the Antares Neutrino telescope in the Mediterranean Sea. Therefore, acoustic sensor hardware has to be developed which is both capable of operation under the hostile conditions of the deep sea and at the same time provide...

This paper presents a novel model-based method for in-situ estimation of sound reflection coefficients in acoustic enclosures. The method uses a modeling engine for simulation of acoustic propagation and generation of the spatial pseudospectrum using a beamforming technique. The simulated pseudospectrum is matched with the measured pseudospectrum acquired by a real beamforming microphone array ...

Since the mid 1990s, acoustics research has been undertaken relating to the sound zone problem-using loudspeakers to deliver a region of high sound pressure while simultaneously creating an area where the sound is suppressed-in order to facilitate independent listening within the same acoustic enclosure. The published solutions to the sound zone problem are derived from areas such as wave field...

A wave-packet ansatz is used to model noise generation by organized, large-scale structures. The spectrum of the acoustic field is expressed in terms of two-point space-time correlations of hydrodynamic pressure on a conical surface surrounding the jet plume. The surface is sufficiently near the turbulent flow region to be dominated by hydrodynamic disturbances, yet sufficiently far that the wa...

In 1976, Hughes and Thompson introduced the idea of steering the maximum response of a linear array by amplitude weighting the output signals of the elements, thus eliminating the need for time delays or phase-shift networks. Currently that amplitude-steered array concept is being extended to a broadband two-dimensional array that can be used for real-time three-dimensional imaging. In shifting...

In this paper, we attempt to unify two array processing frameworks viz, Acoustic Vector Sensor (AVS) and level nested enhance the Degrees of Freedom (DoF) significantly beyond limit that is attained by a Uniform Linear Hydrophone Array (ULA) with specified number sensors. The major focus design line architecture which provides high resolution unambiguous bearing estimation increased spatial nul...

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Sound can levitate objects of different sizes and materials through air, water and tissue. This allows us to manipulate cells, liquids, compounds or living things without touching or contaminating them. However, acoustic levitation has required the targets to be enclosed with acoustic elements or had limited manoeuvrability. Here we optimize the phases used to drive an ultrasonic phased array a...