Disclosed is a method for determining a difference in depth or a lateral distance in relation to the vertical between two points of an underwater environment, in particular by measuring a propagation time of a sound wave. The determination is based on a single-layer model of the environment in which the wave is supposed to propagate in a straight line along an effective propagation direction, at a mean velocity that is independent of the propagation direction. Also disclosed is a method for determining the profile of the mean velocity based on the measurements of differences in depths per se, a determination of the local velocity profile over the variation interval of the sounded depths, and a related sonar system.

A transducer assembly comprises a housing and a plurality of frequency steered transducer array elements. Each of the transducer array elements includes a plurality of piezoelectric elements. The frequency steered transducer array elements are configured to receive a transmit electronic signal including a plurality of frequency components and to transmit an array of sonar beams into a body of water. Each sonar beam is transmitted in an angular direction that varies according to one of the frequency components of the transmit electronic signal. The frequency steered transducer array elements are positioned within the housing in a fan-shaped configuration where an end section of at least two of the frequency steered transducer array elements are within an intersection range of each other.

Acoustic measurement systems include an enclosure having a high efficiency yet very thin acoustic absorber coating portions thereof, in order to diminish background reflections. The thin acoustic absorber includes a reflective sublayer having a periodic array of indentations on its surface. The periodic array of indentations can be one-dimensional or two dimensional. The thin acoustic absorber further includes a thin absorbing layer overlaid on the reflective sublayer, and typically formed of a viscoelastic foam. The thin acoustic absorber possesses unprecedented absorption efficiency across a broad frequency range and at normal or oblique angles of incidence.

Sonar systems and related methods are provided. A sonar system includes a transducer array having a transverse axis and a longitudinal axis disposed perpendicularly thereto. A processor is operative to associate signals with a plurality of transducers in the transducer array so as to form a first acoustic beam, which propagates in a beam first direction and has a first beam width in a first transverse plane. The first transverse plane extends along the beam first direction and contains the transverse axis of the transducer array. A beam spreading device having a curved surface is positioned relative to the transducer array such that the first acoustic beam impinges on the curved surface. Following impingement on the curved surface, the first acoustic beam propagates in a beam second direction and has a second beam width in a second transverse plane. The second beam width is greater than the first beam width.

A semi-passive acoustic transponder providing identity information related to the transponder when it is reflecting a received pulsed acoustic signal underwater. The transponder includes a memory unit holding ID-sequence data controlling operation of the switching device, and an electronic circuit includes frequency adjusting means for adjusting the frequency and duration of the switch such that the duration of the ID-sequence data is shorter than the duration of pulses of the received acoustic signal. Additionally, a method and system may provide position and identity information related to one or more of said semi-passive acoustic transponders.

An ultrasonic cleaning equipment (1) according to the present invention includes a treatment tank (10) that stores a cleaning liquid that cleans an object to be cleaned and in which the object to be cleaned is immersed; an ultrasonic application mechanism (20) that applies ultrasonic waves to the cleaning liquid retained in an interior of the treatment tank; and a curved surface member (30) that is located in a range defined by an angle of inclination from a perpendicular direction in an end portion of a vibrating surface of the ultrasonic application mechanism to an outside with respect to the vibrating surface and that is held on a wall surface and/or a bottom surface of the treatment tank.

A device for use in a medium comprising a medium vibro-acoustic impedance. The device includes an elastic material including a plurality of unit cells. The plurality of unit cells includes a first unit cell. The first unit cell includes a first unit-cell joint comprising a first unit-cell joint wall defining a first joint central void, a first unit-cell joint inclusion located in the first joint central void, and at least two first unit-cell arms connected to and extending away from the first unit-cell joint. The elastic material includes an elastic-material vibro-acoustic impedance. The elastic-material vibro-acoustic impedance and the medium vibro-acoustic impedance are sufficiently vibro-acoustically impedance-matched to couple time-varying, propagating vibro-acoustic fields between said elastic material and the medium.

A transducer assembly comprises a housing and a plurality of frequency steered transducer array elements. Each of the transducer array elements includes a plurality of piezoelectric elements. The frequency steered transducer array elements are configured to receive a transmit electronic signal including a plurality of frequency components and to transmit an array of sonar beams into a body of water. Each sonar beam is transmitted in an angular direction that varies according to one of the frequency components of the transmit electronic signal. The frequency steered transducer array elements are positioned within the housing in a fan-shaped configuration where an end section of at least two of the frequency steered transducer array elements are within an intersection range of each other.

This invention claims a patent on the process of propagating soundwaves through bodies of water, such as oceans, to produce and direct winds, for the purpose of managing aerial weather systems. Propagating soundwaves within water can generate and direct wind for many purposes. One purpose is to effectively weaken storms, by directing wind-shear against a storm's momentum, and stripping it of precipitation. Another purpose is to guide atmospheric rivers, and manually re-direct clouds in the precipitation cycle. This inventive process grants methods to mitigate dangerous weather patterns, such as droughts and hurricanes. The invention introduces a new subject matter that distinguishes it from other inventions relevant to underwater acoustics: manual processes to moderate weather.

An underwater positioning system comprises a plurality of underwater beacons. A beacon, in response to a signal sent by an underwater vehicle, responds with a signal comprising one or more characteristics to identify the beacon. Components of an access algorithm are provided to the underwater vehicle. The access algorithm determines a location of the beacon based on the beacon's identity. A position of the vehicle is determined based at least in part on the location of the beacon.