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Velocity of sound and air density
Paul_ 2012
post May 24 2013, 02:35
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Having started at the beginning, there are plenty of articles quoting the velocity of sound at sea level, and how the velocity of sound increases due to temperature rise and the corresponding reduction air density. Not being entirely happy with this concept I have found another view point.
http://www.sengpielaudio.com/calculator-speedsound.htm
Im thinking that the latter is probably correct.
Please correct me if this is not so.
Paul

apologies if this is not the correct forum
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drewfx
post May 24 2013, 19:24
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If you take the formula given in the link:

c=(γ*p/ρ)1/2

and combine it with:

pV=nRT

you end up getting T and a bunch of constants:

c=(γ*R*T/M)1/2

where
γ = the adiabatic constant, characteristic of the specific gas (about 1.4 for air).
R = the Ideal Gas Constant (8.3144621)
T = temperature in K
M = the Molecular mass (about .02896 kg/mol for air)


[EDIT: oops, I transcribed things wrong -

M is given in kg/kmol which is ~28.96 for air, but I wanted kg/mol so I divided by 1000. But I should have done that in the formula:

c=(γ*R*T*1000/M)1/2

]

This post has been edited by drewfx: May 24 2013, 19:59
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