Refraction, in
acoustics
Acoustics is a branch of physics that deals with the study of mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound. A scientist who works in the field of acoustics is an acoustician ...
, comparable to the
refraction
In physics, refraction is the redirection of a wave as it passes from one transmission medium, medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commo ...
of
electromagnetic radiation
In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength ...
, is the bending of sound propagation trajectories (rays) in inhomogeneous
elastic
Elastic is a word often used to describe or identify certain types of elastomer, Elastic (notion), elastic used in garments or stretch fabric, stretchable fabrics.
Elastic may also refer to:
Alternative name
* Rubber band, ring-shaped band of rub ...
media (gases, liquids, and solids) in which the wave velocity is a function of spatial coordinates. Bending of acoustic rays in layered inhomogeneous media occurs towards a layer with a smaller sound velocity. This effect is responsible for guided propagation of sound waves over long distances in the ocean and in the atmosphere.
In the atmosphere, vertical gradients of wind speed and temperature lead to refraction.
The wind speed is usually increasing with height, which leads to a downward bending of the sound rays towards the ground. The same holds if the temperature is increasing with height (
inversion). If the temperature is decreasing with height and the wind speed is low, sound rays are bent upwards.
See also
*
Atmospheric refraction
Atmospheric refraction is the deviation of light or other electromagnetic wave from a straight line as it passes through the atmosphere due to the variation in air density as a function of height. This refraction is due to the velocity of light ...
*
Deep sound channel
Deep or The Deep may refer to:
Places United States
* Deep Creek (Appomattox River tributary), Virginia
* Deep Creek (Great Salt Lake), Idaho and Utah
* Deep Creek (Mahantango Creek tributary), Pennsylvania
* Deep Creek (Mojave River tributary ...
*
Sound speed gradient
In acoustics, the sound speed gradient is the rate of change of the speed of sound with distance, for example with depth in the ocean,
or height in the Earth's atmosphere. A sound speed gradient leads to refraction of sound wavefronts in the dire ...
*
Underwater acoustics
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. The water may be in the oce ...
References
Further reading
* P.M. Morse and K.U. Ingard, ''Theoretical Acoustics'', Princeton University Press, 1986.
Acoustics
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