A sound source for acoustic communication, navigation, and networking of an underwater glider may include a cylindrical body, a rigid front section disposed anteriorly to the cylindrical body, a plurality of metal rods, a resonant pipe surrounding the rods, and a rod-mounted piezo-ceramic transducer disposed between the body and the front section. Each rod may be attached at a first end to an anterior portion of the body and at a second end to a posterior portion of the front section. The pipe may be disposed between the body and the front section. The transducer may be disposed within the pipe. A posterior end of the pipe may be separated from the anterior portion of the body by a first orifice, and an anterior end of the pipe may be separated from the posterior portion of the front section by a second orifice.

Techniques are disclosed for systems and methods to provide accurate and reliable compact sonar systems for mobile structures. A sonar system includes multiple sensor channels, each comprising a sonar transmitter and a sonar receiver, and a logic device configured to provide control signals and receive sensor signals from the sensor channels. The logic device is configured to provide transmission signals to sonar transducer assemblies, where signal patterns of the transmission signals are differentiated based at least in part on frequency content. Acoustic returns are processed using the signal patterns to reduce inter-channel pickup between the sensor channels. Resulting sonar data and/or imagery may be displayed to a user and/or used to adjust a steering actuator, a propulsion system thrust, and/or other operational systems of the mobile structure.

Apparatus for controlling bio-organisms in bodies of water. The algae control system includes a power unit and a transducer unit that radiates in multiple directions. The transducer unit includes a variable power driver and a transducer subassembly. The power from the driver varies to maintain a maximum, constant transducer sonic output over its bandwidth. The transducer assembly includes at least one transducer that includes a pair of blocks with at least one piezoelectric element therebetween. One embodiment has a single, disc-shaped element adhesively secured between said blocks. The transducer is excited by applying power to the pair of blocks. Another embodiment has at least one ring-shaped elements compressed between the two blocks by way of a fastener. The transducer is excited by applying power, in one embodiment, between the blocks and a conductor between a pair of ring-shaped elements, or in another embodiment, between the pair of blocks.

Apparatus for controlling algae and bio-organisms in bodies of fluids, such as water. The algae control system includes a power unit and a transducer unit that includes a sonic head that radiates in multiple directions. The power unit connects to various power sources, including a mains supply connection, a solar panel array, and/or a battery. The power unit is electrically connected to the transducer unit. The sonic head includes a driver and a transducer subassembly. The driver excites the transducer assembly to emit ultrasonic waves at various frequencies with varying durations of on/off periods. Emissions at a high density of frequencies are enabled by the transducers. The frequencies include the critical structural resonant frequency for each microorganism to be controlled. The power unit and driver each include a processor in communication with each other. The processors store and execute a program for a selected application configuration.

In the system, two ultrasonic transducers, which form a pair and each have a piezoelectric ceramic plate-shaped element with a rectangular geometry, can be fastened to a surface of a component. The two ultrasonic transducers are arranged at a distance from one another such that there is no direct mechanical contact and they are arranged beside one another with a parallel orientation of their central longitudinal axes. The two elements have a different polarization along their width and are connected with the same polarity to an electrical voltage source. The two plate-shaped elements can also have an identical polarization along their width and can be connected in this case with opposite polarity to an electrical voltage source. At least one ultrasonic transducer and/or at least one further ultrasonic transducer is/are designed to detect ultrasonic waves reflected by defects and/or shear waves simultaneously emitted by the two ultrasonic transducers.

Systems and methods for the ultrasonic disruption of biofilm and algae growth on underwater structures utilize an ultrasonic actuator that produces a natural frequency in the ultrasonic range. In some embodiments, the ultrasonic actuator includes one or more piezoelectric transducers.

A transducer for non-invasive measurement includes: a piezoelectric element; a base plate; and driver electronics. The piezoelectric element is mounted to a first face of the base plate. A second face of the base plate is mountable to a wall of a vessel that holds a liquid. The driver electronics drive the piezoelectric element at a plurality of activation frequencies. When the second face of the base plate is mounted to the wall of the vessel, the transducer when activated excites acoustic waves in the base plate and to launch an acoustic wave into the liquid. The transducer is designed such that an angular divergence of the acoustic wave launched into the liquid varies as a function of at least the activation frequency and a dimension of an emitter.

A transducer is provided, which includes an oscillator and a broadbanded matching circuit. In the oscillator, a peak frequency corresponding to a peak transmission sensitivity may separate from a center frequency in a given bandwidth, and a transmission sensitivity may increase as a frequency separates from the peak frequency with respect to the center frequency. The broadbanded matching circuit may be configured to perform an impedance matching so that the transmission sensitivity of the oscillator at the peak frequency becomes substantially equal to the transmission sensitivity of the oscillator at the center frequency.

Systems and methods for the ultrasonic disruption of biofilm and algae growth on underwater structures utilize an ultrasonic actuator (10) that produces a natural frequency in the ultrasonic range. In some embodiments, the ultrasonic actuator (10) includes one or more piezoelectric transducers (110).

The method and system uses ultrasound (US) transducers in contact with an inboard surface underwater portions of marine vessels or structures. By first digitally generating disruptive, multi-frequency, interfering US waveform signals (complex waveforms, typically replicating a Bessel function) and then converting the signals into analog, the transducers generate disruptive, multi-frequency, interfering US waveforms through the underwater portions of the marine vessels and structures which waveforms disrupt unwanted marine growth on the water-side of the vessel or structure. The digital signals, and also the analog signals, are complex waveform signals, typically produced with a Bessel function. The US transducers are either circular membrane transducers or surface transducers. A computer processor coupled to a memory, generates the complex waveform signals fed to the US transducers.