Considerations for the design of inlet flow conditioners for static fan noise testing
Abstract
Reductions in distortion tone level of up to 10 dB have already been achieved with a hemispherical honeycomb flow conditioner. Ways of achieving further reductions are investigated in acoustic and aerodynamic tests on flow conditioner elements. Turbulence reduction measurements indicate that adding a gauze downstream of the honeycomb is much more effective than increasing the cell depth. Some tests concerning the importance of the duct boundary layer region which shed further light on earlier work are discussed. Aspects relevant to outdoor full-scale engine tests are emphasized and some preliminary results from such tests are given.
- Publication:
-
American Institute of Aeronautics and Astronautics Conference
- Pub Date:
- March 1979
- Bibcode:
- 1979aiaa.confR....G
- Keywords:
-
- Aeroacoustics;
- Inlet Flow;
- Jet Aircraft Noise;
- Noise Reduction;
- Turbofan Engines;
- Anechoic Chambers;
- Ducted Fans;
- Ducted Flow;
- Engine Tests;
- Far Fields;
- Flow Distortion;
- Gauze;
- Honeycomb Structures;
- Mach Number;
- Sound Transmission;
- Static Tests;
- Turbulent Boundary Layer;
- Turbulent Flow;
- Wind Effects;
- Acoustics