Microphone-Array Measurements of a Model Scale Contra-Rotating Open Rotor in a Reverberant Open Wind-Tunnel
Funke, St. and Kim, L. and Siller, H. (2011) Microphone-Array Measurements of a Model Scale Contra-Rotating Open Rotor in a Reverberant Open Wind-Tunnel. In: Proceedings 17th AIAA / CEAS Aeroacoustics Conference (32nd Aeroacoustics Conference). AIAA. 17th AIAA / CEAS Aeroacoustics Conference (32nd AIAA Aeroacoustics Conference), 05.06. - 08.06.2011, Portland, USA.
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The DLR department of engine acoustics performed acoustic measurements of a contra-rotating open-rotor (CROR) model with a linear microphone array in the T-104 open wind-tunnel at TsAGI. The microphone data is corrected for shear-layer effects using the model of an infinitely thin shear layer by Amiet. Investigations of the room-acoustics of the test hall show strong reflections from the ceiling and two side walls, which cause strong interference patterns at the microphone positions. The acoustic change between different rotor confgurations, like different rotor spacings and an upstream mounted mock pylon, is shown with spatially averaged spectra. The evaluation of the source directivities is strongly influenced by the interference patterns of the reflections in the test hall. The rotor tones can be localized at the correct position with classical beamforming. The inverse method SODIX is used to model the directivities of the broadband sound-sources of the CROR. Green's functions that take the shear layer and the first-order reflections into account were implemented. The accuracy of these correction methods could be investigated with the directive SODIX results. The shear-layer model gives accurate results for emission angles < 100° while all modeled sources move downstream for larger emission angles. Corrections for the first-order reflections of the test hall show an increased spatial resolution of the SODIX results and a suppression of artificial sources.
|Document Type:||Conference or Workshop Item (Paper)|
|Title:||Microphone-Array Measurements of a Model Scale Contra-Rotating Open Rotor in a Reverberant Open Wind-Tunnel|
|Journal or Publication Title:||Proceedings 17th AIAA / CEAS Aeroacoustics Conference (32nd Aeroacoustics Conference)|
|In ISI Web of Science:||No|
|Keywords:||Mikrofonarray, Windkanal, Offene gegenläufige Rotoren, Schallquellenlokalisierung, SODIX, Beamforming, Scherschicht, Reflexion, Microphone-Array, Wind-Tunnel, CROR, Contra-Rotating Open Rotor, Source Localization, Shear Layer, Reverberation|
|Event Title:||17th AIAA / CEAS Aeroacoustics Conference (32nd AIAA Aeroacoustics Conference)|
|Event Location:||Portland, USA|
|Event Type:||international Conference|
|Event Dates:||05.06. - 08.06.2011|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Aeronautics|
|HGF - Program Themes:||L ER - Engine Research|
|DLR - Research area:||Aeronautics|
|DLR - Program:||L ER - Engine Research|
|DLR - Research theme (Project):||L - Turbine Technologies|
|Institutes and Institutions:||Institute of Propulsion Technology > Engine Acoustic|
|Deposited By:||Balbir Kaur|
|Deposited On:||20 Jan 2012 14:53|
|Last Modified:||09 Feb 2012 15:46|
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