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In acoustics, the sound speed gradient is the rate of change of the speed of sound with depth in the ocean,[1] or height in the Earth's atmosphere. A sound speed gradient leads to refraction of sound wavefronts in the direction of lower sound speed, causing the sound rays to follow a curved path. The radius of curvature of the sound path is inversely proportional to the gradient.[2] Acoustics is a branch of physics and is the study of sound (mechanical waves in gases, liquids, and solids). ...
The speed of sound is a term used to describe the velocity of sound waves passing through an elastic medium. ...
Animated map exhibiting the worlds oceanic waters. ...
Layers of Atmosphere - not to scale (NOAA)[3] Earths atmosphere is a layer of gases surrounding the planet Earth and retained by the Earths gravity. ...
The straw seems to be broken, due to refraction of light as it emerges into the air. ...
In optics, a wavefront is the locus (a line or surface in an electromagnetic wave) of points having the same phase. ...
When the sun warms the Earth's surface, there is a negative temperature gradient in atmosphere. The speed of sound decreases with decreasing temperature, so this also creates a negative sound speed gradient.[3] The sound wave front travels faster near the ground, so the sound is refracted upward, away from listeners on the ground, creating an acoustic shadow at some distance from the source.[4] The opposite effect happens when the ground is covered with snow, or in the morning over water, when the sound speed gradient is positive. In this case, sound waves can be refracted from the upper levels down to the surface.[3] The temperature gradient in a given direction from a given spatial starting point is the rate at which temperature changes relative to distance in that direction from that point. ...
The speed of sound is a term used to describe the velocity of sound waves passing through an elastic medium. ...
The straw seems to be broken, due to refraction of light as it emerges into the air. ...
An acoustic shadow is an area through which sound waves fail to propagate, due to topographical obstructions or disruption of the waves via phenomena such as wind currents. ...
In underwater acoustics, when there is a zero sound speed gradient, values of sound speed have the same "isospeed" in all parts of a given water column (there is no change in sound speed with depth).[1] The same effect happens in an isothermal atmosphere with the ideal gas assumption. An ideal gas or perfect gas is a hypothetical gas consisting of identical particles of zero volume, with no intermolecular forces. ...
References - ^ a b (August 2006) Navy Supplement to the DOD Dictionary of Military and Associated Terms. Department Of The Navy. NTRP 1-02.
- ^ Lamancusa, J. S. (2000). "10. Outdoor sound propagation", Noise Control (pdf), ME 458: Engineering Noise Control, Penn State University, pp. 10.6-10.7.
- ^ a b Ahnert, Wolfgang (1999). Sound Reinforcement Engineering. Taylor & Francis, p. 40.
- ^ Everest, F. (2001). The Master Handbook of Acoustics. New York: McGraw-Hill, pp. 262-263. ISBN 0071360972.
The United States Navy, also known as the USN or the U.S. Navy, is a branch of the United States armed forces responsible for conducting naval operations. ...
The Pennsylvania State University The Pennsylvania State University (commonly known as Penn State) is a state-related land-grant university in Pennsylvania, with over 80,000 students at 24 campuses throughout the state. ...
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