Environmental Engineering Reference
In-Depth Information
II
means the zone with re
fl
ected shock waves passing through. q 1 and q 2 are
fl
ow
rates of air in
zones separately.
After passing the shock wave fronts, both the velocity/rate and direction of air
change. The tangential component parallel to shock wave fronts remains constant,
and the normal component becomes smaller. So the direction of
I
and
II
fl
ow turns toward
the wall/surface. Below equation is obtained from Fig. 2.41 .
u 1 ¼ q 1 cos
ð
u 1 h
Þ
q 0 cos
In the two sides of incident wave fronts, both energy and momentum are
conserved.
q 0 q 0 sin
u 1 ¼ q 1 q 1 sin
ð
u 1 h
Þ
P 0 þ q 0 q 0 sin 2
u 0 ¼ q 1 q 1 sin 2
ð
u 1 h
Þ P 1
Likewise, the incident
fl
flow in
I
zone is q 1 .Itin
fl
ows
II
zone with an angle of
u 2 þ h
from the fronts OR of re
fl
ected waves. Because of the impact of velocity
component q 1 cos
ow q 2 directs outward and it is parallel
with the rigid surface. For the two sides of re
ð
u 2 þ h
Þ
, the re
fl
ected
fl
fl
ected waves, below equations are
established.
q 2 cos
u 2 ¼ q 1 cos
ð
u 2 þ h
Þ
q 2 q 2 sin
u 2 ¼ q 1 q 1 sin
ð
u 1 þ h
Þ
q 2 q 2 sin 2
u 2 þ P 2 ¼ q 1 q 1 sin 2
ð
u 2 þ h
Þ P 1
The impact adiabatic function of incident waves and re
fl
ected waves are
q 1
ð
k þ
1
Þ P 1 þ k
ð
1
Þ P 0
q 0 ¼
ð
k
1
Þ P 1 þ k þ
ð
1
Þ P 0
and
q 2
q 1 ¼
ð
k þ
1
Þ P 2 þ k
ð
1
Þ P 1
ð
k
1
Þ P 2 þ k þ
ð
1
Þ P 1
are obtainable from above equations. The calculation
process is very complex. As a matter of convenience, the oblique re
P 2 ; q 2 ; u 2 ; q 1
and
ʸ
fl
ection is
simpli
ed to Eq. 2.100 .
6 D P 1
D P 1 þ
7P 0 cos 2
D P 2 ¼
ð
1
þ
cos
u
Þ D P 1 þ
u 1
ð
2
:
100
Þ
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