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Old   August 24, 2013, 10:30
Default sutherland law?
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TPRPR1
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hi
i have a question regarding the Sutherland law
for air
s=110
mo=1.715
t0=273.11
does the co-efficients vary with altitude of air?
for example for 10000m mo=1.458e^-5
how do i calculate S?
thanks in advance

Last edited by tprpr1; August 24, 2013 at 13:33.
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Old   August 27, 2013, 05:37
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Hi
whats "mo"?
didn't you get anything by searching?
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Old   August 27, 2013, 06:49
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s=sutherland temperature
m0=reference viscosity
to=reference temperature
i looked at several places on the net
to=remains the same for all
s and m0 changes for different materials
However mo will change for different altitude for air(data available)
but i do not know how to calculate s corresponding to the new mo
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Old   August 27, 2013, 07:23
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sutherland law?

Anderson too in the Fundamentals of Aerodynamics 5th Edition, gives S=110
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Old   August 27, 2013, 08:42
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Hi, I would say that for a certain fluid the coefficients are constant, viscosity only changes with temperature. The viscosity of air varies indirectly with altitude through temperature.

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Old   August 27, 2013, 09:19
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Quote:
Originally Posted by michujo View Post
Hi, I would say that for a certain fluid the coefficients are constant, viscosity only changes with temperature. The viscosity of air varies indirectly with altitude through temperature.

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Michujo.
If you take air to be an ideal gas
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Old   August 27, 2013, 13:14
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Hi, can you please elaborate?

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Old   August 27, 2013, 13:20
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Quote:
Originally Posted by michujo View Post
Hi, can you please elaborate?

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I hadn't read carefully your post and I didn't know how to delete my post
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Old   August 27, 2013, 15:26
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thank you all for replying

so in other words the 3 coefficients mo ,to,s remain the same for any altitude as long as im taking air as ideal gas in fluent

the actual viscosity m will vary as a function of temperature t.
that clears my doubt .thank you
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