BISOPE series
20- Why is there a difference in the speed of sound in solids and gases?
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Why is there a difference in the speed of sound in
solids and gases?
The speed at which sound waves propagate through
a medium is the definition of sound speed. The medium itself does not
move, it is the propagation speed of the phase of the sound wave. When looking
at the wavelength as the origin, sound waves in a narrow sense propagate through
the fluid as longitudinal waves (penetrating the medium in the propagation
direction), and their speed varies depending on the conditions of the medium
such as temperature and humidity and the type of medium.
Change in momentum and rate of volume
change
The propagation speed of longitudinal waves is determined by the mechanical
properties of the medium. Considering the change in momentum of the fluid moving
in the piston (vt) with a certain cross-sectional area (A), it can be viewed as
the product of the mass (ρvtA) of the fluid and the change in velocity (u). On
the other hand, when the pressure increase Δp in the moving fluid is obtained,
the initial volume Avt of the fluid in motion is decreased by Aut, so from the
definition of the bulk modulus (;- pressure change/volume change rate)
Velocity of sound, modulus of elasticity -
https://blog.naver.com/vs72
is established At this time, 'B' is the bulk modulus,
and when the medium is a fluid, it corresponds to the volume modulus (volume
change rate), and when the medium is a solid, it corresponds to the Young's
modulus. Since it is larger than the bulk modulus of , the velocity in the
medium of longitudinal waves is ultimately influenced by the difference in the
velocity of sound by the difference in the volume modulus rather than the
difference in the density. V solid > V liquid > V gas !
Difference in speed of sound - https://blog.naver.com/vs72
What is the difference between the speed
of sound and the speed of particles?
As the speed at which sound waves propagate through an
elastic medium, the formula is the same as above, and among them, the speed of sound in the air is expressed
conveniently and c=20.06√T in relation to temperature.
On the other hand, particle velocity (v) is the vibration velocity of
a medium that transmits sound waves, and when it is assumed as a plane wave, it
can be expressed as v=p/ρc. (T: absolute temperature, p: pressure, ρ: density, c: speed of
sound)
Wavelength, particle velocity -
https://blog.naver.com/vs72
speed of sound in different media
All copyright Korea CBM Co., Ltd. written by BISOPE
#vibration measurement, #vibration analysis, #frequency
analysis, #resonance measurement, #resonance analysis, #3-axis vibration,
#accelerometer, #fft, #bearing vibration, #vibration noise education,
#equipment diagnosis, #cbm, #bearing vibration , #building vibration, #gear
movement, #visope, #looseness, #environmental vibration, #rotating machine,
#vibration education, #vibration monitoring, #balancing, #volume modulus,
#sonic velocity, #noise and vibration
All copyright korea CBM written by
BISOPE , vs72@naver.com, 070-4388-0415, www.kCBM.kr
#vibration measurement, #vibration analysis, #frequency
analysis, #resonance measurement, #resonance analysis, #3-axis vibration,
#accelerometer, #fft, #bearing vibration, #vibration noise education,
#equipment diagnosis, #cbm, #bearing vibration , #building vibration, #gear
movement, #visope, #looseness, #environmental vibration, #rotating machine,
#vibration education, #vibration monitoring, #balancing, #volume modulus,
#sonic velocity, #noise and vibration
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