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Problem 9.3
[3]
Given:
Boeing 757
Find:
Point at which transition occurs; Same point at 10,000 m
Solution:
Basic equation
Re
x
ρ
U
⋅
x
⋅
μ
=
Ux
⋅
ν
=
and transition occurs at about
Re
x
51
0
5
×
=
For air at 20
o
C
ν
1.50
10
5
−
×
m
2
s
⋅
=
(Table A.10)
and we are given
U
260
km
hr
⋅
=
Hence
x
p
ν
Re
x
⋅
U
=
x
p
0.104m
=
x
p
10.4cm
=
At 10,000 m
T
223.3 K
⋅
=
(Table A.3)
T
49.8
−
°C
=
We need to estimate
ν
or
μ
at this temperature.
From Appendix A3
μ
bT
⋅
1
S
T
+
=
b
1.458
10
6
−
×
kg
ms
⋅
K
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 Fall '08
 ZOHAR

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