Search results
Results from the WOW.Com Content Network
Output of a computer model of underwater acoustic propagation in a simplified ocean environment. A seafloor map produced by multibeam sonar. Underwater acoustics (also known as hydroacoustics) is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water, its contents and its boundaries.
Underwater acoustic communication is a technique of sending and receiving messages in water. [1] There are several ways of employing such communication but the most common is by using hydrophones . Underwater communication is difficult due to factors such as multi-path propagation , time variations of the channel, small available bandwidth and ...
As sound travels faster and over a larger distance in water than in air, aquatic animals can use sound signals for long-distance communication while terrestrial animals cannot. [4] For example, a blue whale can communicate with another blue whale using sound over thousands of miles across the sea.
Sonar systems are generally used underwater for range finding and detection. Active sonar emits an acoustic signal, or pulse of sound, into the water. The sound bounces off the target object and returns an echo to the sonar transducer. Unlike active sonar, passive sonar does not emit its own signal, which is an advantage for military vessels.
That means targets are undetectable within the circle of Cτ/2 radius, where C is sound speed in water. This area is usually referred to as “dead zone”. If the sonar is close to the surface, bottom or both, (which may happen in shallow water), the dead zone may be greater than Cτ/2 due to a high level of reverberation.
The speed of sound will vary slightly depending on temperature, pressure and salinity; and for precise applications of echosounding, such as hydrography, the speed of sound must also be measured, typically by deploying a sound velocity probe in the water. Echo sounding is a special purpose application of sonar used to locate the bottom.
Partially blind in one eye and with a slightly shut jaw, Brodie might have required "a little extra care," but that didn’t stop Richter, 35, from falling in love when she first saw him on the ...
American low frequency sonar was originally introduced to the general public in a June 1961 Time magazine article, New A.S.W. [Note 1] Project Artemis, the low-frequency sonar used at the time, could fill a whole ocean with searching sound and spot anything sizable that was moving in the water.