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Fan and Compressor
Service & Links
7 December 2010
Aircraft noise stems from both the airframe and the propulsive systems. Airframe noise, defined as the non-propulsive noise of an aircraft in flight, arises from a variety of sources including the turbulent flow around landing gear, slats, flaps and any surface cutouts or protrusions. Although of increasing importance, airframe noise sources remain, at present, secondary to those of the propulsive systems. Propulsive noise itself has traditionally been dominated by jet mixing noise. In particular the introduction of the bypass engine concept, have however drastically reduced this noise source. For modern high-bypass-ratio turbofan engines, fan noise, radiated forward through the inlet and aft through the fan exhaust duct is now the dominant source of noise during both takeoff and landing.
DLR-Institute of Propulsion Technology-Engine Acoustics Department
DLR-Institut für Lufttransportsysteme
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