Page 273 - 48Fundamentals of Compressible Fluid Mechanics
P. 273
13.4. SOLUTION OF MACH ANGLE 7 8 235
5
4
4
9
"
"-"1"
The shock angle, can be calculated from 6 6 7 7
7 8
5
The deflection angle for such shock angle with Mach number is
) "
) 9 =),"
c 7 8
4
4
4
)
"9
) "
9
) =)
For the last calculation is clear that the government proposed schematic of
+
the double wedge is conflict with boundary condition. The flow in zone 3 will flow
7 8
into the wall in about ) . In reality the flow of double wedge produce curved shock
surfaces with several zones. Only far away for the double wedge the flow behaves
as only angle exist of + .
Example 13.7:
Calculate the flow deflection angle and other parameters downstream when Mach
. Assume and
)
and
,' ,
"
angle of
SOLUTION " )(
$
while below maximum deflection means that the it
is a weak shock. Yet, the Upstream Mach number, , has to be determined
) &
The angle of Mach angle of
"
-
With this Mach number and the Mach deflection either using the Table or the figure
or POTTO-GDC results in
=)$
"
c 7 8
4
4
4
9 ),
1
+1"
-"
)
The relationship for the temperature and pressure can be obtained by using equa-
tion (13.15) and (13.13) or simply converting the to perpendicular component.
7 8
From the Table (5.1) or GDC the following can be obtained. 9
-
+
5
4
4
78
6
7
78
-"
9
-9
-"
"
+-+-9
+
9-)09
5
6
7
