Page 66 - 48Fundamentals of Compressible Fluid Mechanics

28 CHAPTER 3. SPEED OF SOUND

and hence

(3.12)

# %
#
$#
#
&%

is defined for ideal gas as
, and equation (3.12) can be

written as
#
Remember that
(3.13)
Example 3.2:
, (a) utilizes the
steam table (b) assuming ideal gas.
SOLUTION and
The solution can be estimated by using the data from steam table 3
Calculate the speed of sound in water vapor at
(3.14)

%

: s = 6.9563
= 6.61376"$#
and
At
%!
After interpretation of the temperature: % % %
%

: s = 7.0100
At %&
and
= 6.46956"#
%

%
and substituting into the equation yields %
and

: s = 6.8226
At %&
= 7.13216"#
%!
(3.15)
: s
6.9563

%+
At %&
and
'
)(*
6.94199"#

%

1
for ideal gas assumption (data taken from Van Wylen and Sontag, Clas-
sical Thermodynamics, table A 8.)
.(/%
-,
0

%

Note that a better approximation can be done with a steam table, and it
1
will be part of the future program (potto–GDC).
# #

-2

( 3 4

(/
('(

3 This data is taken form Van Wylen and Sontag “Fundamentals of Classical Thermodynamics” 2nd
edition