# HMWK 22,23 ```ME3251 Flow of Compressible Fluids
Dr. T. J. Barber
Spring 2013
Problem 22:
Consider a supersonic flow with an upstream Mach number of 4 and a pressure of 1 atm.
This flow is first expanded around an expansion corner with 1 = 15 degrees, and then
compressed through a compression corner with an equal angle of 2 = 15 degrees so that
it is returned to the original upstream direction. Calculate the Mach number and pressure
downstream of the final compression corner. Use both shock – expansion and weak shock
– expansion theory.
Problem 23
Using both shock-expansion theory and weak-shock theory, calculate the lift and drag
[coefficient] on two symmetrical diamond airfoils, one with a semiangle  = 30 and one
of  = 150. Both are at zero angle of attack to the freestream. The upstream Mach
number and pressure are 2.0 and 2116 lb/ft2 respectively. The maximum thickness of the
airfoil is t = 0.5 ft. Assume a unit length of 1 ft in the spanwise direction [perpendicular
to the page]. Compare the results and explain them.
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