Page 280 - 48Fundamentals of Compressible Fluid Mechanics

242 CHAPTER 13. OBLIQUE-SHOCK

Example 13.14:
The previous example give raise to another question the order of the deflection
angles. Consider the same values as previous analysis, if oblique shock with first
and or opposite order make a difference ( 9 )? If not
what order make bigger entropy production or pressure loss? (No general proof is
with angle of 9
needed).
SOLUTION
Waiting for the solution

13.4.13 Optimization of Suction Section Design
Under heavy construction please ignore
The question raises what is the optimum design for inlet suction unit. The
are several considerations that have to be taken into account aside to supersonic
flow which include for example the material strength consideration and operation
factors.
The optimum deflection angle is a function of the Mach number range in with
suction section is operated in. The are researchers that suggest that the numerical
is presentation of the ex-
perimental works is useful
here? or present the nu- work with possibility to work the abrupt solution.
merical works? Perhaps to
present the simplified model.
13.5 Summary
As normal shock, the oblique shock the upstream Mach number, is always

could be larger or smaller then 1. The perpendicular component of the downstream
is always smaller than 1. For given and deflection angle,

c there could be three solutions: the first one is the “impossible” solution in case

Mach number,
where D is negative two the weak shock, and three the strong shock. When D is

greater than 1. However, not as the normal shock downstream Mach number,
positive there no physical solution and only normal shock exist. When D is equal

to zero, a spacial case is created for the weak and strong solution are equal (for
, for large deflection angle, there is possibility
of no two-dimensional solution resulting in a detached shock case.
large deflection angle). When
13.6 Appendix: Oblique Shock Stability Analysis

The stability analysis is an
analysis which answer the
question what happen if for Unstable Stable
some reasons, the situation
moves away from the ex-
pected solution. If the an-
swer turned out to be that Fig. 13.21: Typical examples of of unstable and stable situ-
situation will return to its ations