5. (12 Points): Describe the phenomenon of a stall in an aircraft compressor, including the flight characteristics that contribute to the stall. Be sure to discuss the definitions and causes of flutter and buffet. If the stall continues, how can this influence flow in the combustor? 6. (8 Points): Regarding flow diffusion in a compressor, discuss the definition of a stage-based figure of merit. What does this figure tell us? What is an optimal degree of reaction and why? 7. (8 Points): Why are axial flow compressors preferred over centrifugal compressors for large turbojet engines? Chapter 9: 8. (10 Points): The inlet static pressure to an impeller is pr=100 kPa and its exit static pressure is ps = 200 kPu with inlet relative dynamic pressure (r = 140 kPa. Treating the impeller as a diffuser, assuming y=1.4, calculate: a. Inlet relative Mach number, M b. Static pressure recovery coefficient, Cra 9. (12 Points): Discuss the three types of centrifugal compressor impeller geometries and provide an example of an engine using a centrifugal compressor with each type 10. (10 Points): Discuss the main purpose of the inducer and radial diffuser in a centrifugal- low compressor.