Passive bypass for mitigation of inlet buzz in supersonic or hypersonic air-breathing engines

A passive bypass for an inlet to an air-breathing engine, said inlet defined as a void space between a flight vehicle body and a cowling, said inlet including a throat and a diffuser configured to supply airflow to the engine, said passive bypass comprising:

• a plurality of lower channels in the cowling and operatively coupled to the diffuser at an inner surface of the cowling and swept forward towards the throat;
• a plenum in the cowling operatively coupled to the plurality of lower openings;
• and
• a plurality of upper channels in the cowling and operatively coupled to the plenum and swept back away from the throat to an outer surface of the cowling;
• wherein when the air-breathing engine is off, supersonic airflow into the inlet produces a shock wave that is established in the diffuser, wherein all subsequent airflow entering the inlet is diverted forward through the lower openings into the plenum where the pressure is reduced and then directed aft out of the plurality of upper openings into the atmosphere,
• wherein when the air-breathing engine is on, a serpentine path through the plurality of lower openings, the plenum and the plurality of upper openings limits the amount of airflow that leaks out of the cowling.

A passive bypass for an inlet to an air-breathing engine, said inlet defined as a void space between a flight vehicle body and a cowling, said inlet including a throat and a diffuser configured to supply airflow to the engine, said passive bypass comprising:

• a plurality of lower channels in the cowling and operatively coupled to the diffuser at an inner surface of the cowling and swept forward towards the throat;
• a plenum in the cowling operatively coupled to the plurality of lower openings;
• and
• a plurality of upper channels in the cowling and operatively coupled to the plenum and swept back away from the throat to an outer surface of the cowling;
• wherein when the air-breathing engine is on,
• during normal operation, supersonic airflow into the inlet produces a shock wave that is established in the diffuser aft of the passive bypass such that an amount of airflow that leaks out through the passive bypass is limited,
• wherein if the shock wave is disturbed and moves forward toward the throat, airflow entering the inlet is diverted forward through the lower openings into the plenum where the pressure is reduced and then directed aft out of the plurality of upper openings into the atmosphere to prevent the shock wave from reaching the throat.