Aerospace Propulsion Assignment 6 — Off-Design and Unstarted Inlets  
Instructions
Write your solutions in single column format, with one statement following another vertically. Write your solutions neatly so that they are easy to read and verify. Don't write one line with more than two equal signs. Highlight your answers using a box. Solve the problems starting from the Aerospace Propulsion Tables. Do not use any other document to solve the problems.
05.04.14
Question #1
A ramjet is to fly at 12,000 m altitude with a speed of 3200 km/hr.
(a)  Design the best fixed-geometry, convergent-divergent diffuser for this aircraft, and compute for it the least percent loss in stagnation pressure.
(b)  Suppose that it were possible to overspeed the aircraft to 3840 km/hr. Design the best convergent-divergent diffuser which could then be used, and find for it the least percent loss in stagnation pressure at the operating speed of 3200 km/hr.
04.27.23
Question #2
A supersonic aircraft is equipped with a two-dimensional, converging-diverging, variable throat area, intake diffuser. The diffuser is designed for a cruise Mach number of $2.2$. What percent increase in throat area is required to “swallow” the shock? If in the takeoff sequence the aircraft has to “loiter” at Mach 1.8 due to tactical reasons, what percent of mass spill of air occurs, with the rest, of course, passing through the engine, if the diffuser configuration happens to be set for cruise at $M_\infty=2.2$?
Question #3
A two-dimensional internal compression supersonic diffuser is to be designed as shown below for a Mach number of $2.5$. The ratio $h_2/h_1$ is to be chosen so that the diffuser will barely swallow the initial shock, and the ratio $l/h_1$ is to be selected so as to obtain the wave pattern shown.
diffuser.png ./download/file.php?id=11713 ./download/file.php?id=11713&t=1
(a)  Determine $h_2/h_1$ and $l/h_1$
(b)  Neglecting friction compare the overall stagnation-pressure ratio of this diffuser with the stagnation pressure ratio of a diffuser in which a normal shock occurs at Mach number $2.5$.
09.12.23
Answers
1.  -55.8%, -54%.
2.  59.2%, 41.7%.
3.  0.757, 1.87, $0.64\pm 0.03$ (roundoff error), 0.499.
10.18.23
Due on Tuesday October 27th at 23:59. Do Problems #2 and #3 only.
10.21.26
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