PPRuNe Forums - View Single Post - Normal and oblique shocks
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Old 2nd December 2002 | 15:19
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Zeke
 
Joined: May 2000
Posts: 340
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From: Worldwide
Dick,

An example may help with some numbers ...

Say free stream M=1.5 with a wedge of
12 degrees = oblique shock
13 degrees = normal shock

Ratio is the relationship between the value before the shock to after the shock. p = static pressure, pt = total pressure, T =temperature, r = density

For the normal shock
Shock angle = 90 degrees
Mach = 0.701
p ratio = 2.458
pt ratio = 0.929
T ratio = 1.32
r ratio = 1.862

For the oblique shock
Shock angle = 64.371 degrees
Mach = 0.959
p ratio = 1.969
pt ratio = 0.969
T ratio = 1.224
r ratio = 1.608


Q -When comparing a normal and an oblique shockwave, the normal shockwave:

A) has a higher total pressure - no
B) has a higher total temperature - yes
C) has a lower static pressure - no
D) has a lower total pressure - no

The trick question is how in JAR does this improve delivering passengers and freight to the destination safely.

Regards

Z
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