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Old 7th Jun 2014, 20:01
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WeekendFlyer
 
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Pitot-style engine intake above Mach 1

Quick question for any guru-level aerodynamicists or engine intake designers out there. If a subsonic jet engine intake for a high bypass turbofan engine (e.g. as used on most airliners) experiences freestream airflow above Mach 1, what happens? I realise a normal shock will form across the inlet or just inside it but will that be all, or will there be some nasty destructive shock patterns inside the inlet as well? I was wondering if the inlet profile could effectively be seen as a convergent-divergent nozzle by the airflow, thus resulting in supersonic flow entering the divergent duct.

Also, why are smaller pitot intakes (such as those seen on Hawk, Jaguar, etc) fine to use above Mach 1? Clearly they have much sharper lips to the intake and the normal shock sits across the whole inlet area, so presumably behind it the air is all subsonic and the rest of the intake behaves as it would at subsonic speeds.

Any references or diagrams would be much appreciated!
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