John...
I understand what you said about managing intake air so that the engine only receives subsonic air by controlling the shockwaves but why can't the engine accept supersonic air? Is it because of the shockwaves that would develop as it went through the compressor section which would severely disrupt the airflow on the compressor blades?
I understand how a divergent duct can take sonic air and increase it to supersonic but I'm still not quite clear on the intake part and how it contributes to thrust.