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Old 28th Nov 2012, 06:10
  #142 (permalink)  
CliveL
 
Join Date: Dec 2010
Location: Europe
Age: 83
Posts: 286
How far in front of the intake is freestream?
Not closer than the point at which the streamtube that contains the engine flow is first affected by the forward influence of the intake. Otherwise as far ahead of the intake as you wish to define it.
For subsonic intakes the closest point will vary with the ratio of engine mass flow to intake capture mass flow for that flight Mach number and intake area.If in doubt go further forward.
For supersonic intakes it will be the point of the cone for axisymmetric intakes or the leading edge of the ramps if 2D
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