Azimuthal Noise Characteristics of Contra-Rotating Propellers: Results of a Wind Tunnel Model Test.
Gehlhar, B. and Dobrzynski, W. (1990) Azimuthal Noise Characteristics of Contra-Rotating Propellers: Results of a Wind Tunnel Model Test. Inter-Noise '90, 13-15 August 1990, Göteborg.
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Compared to conventional turbofan engines, advanced high speed coaxial/contra-rotating ("CR") propellers promise significant fuel savings. Their noise characteristics, however, differ from those of singe-rotating ("SR") propellers as a consequence of the unavoidable acoustic interaction effects; additional noise is generated by aerodynamic interactions. In the context of an acoustic research program to support the development of future CR-propfans, pilot-type aerodynamic wind tunnel tests on contrarotating model-scale propellers (diameter 0,27 m)were conducted. It was found that, compared to SR-propellers, the noise radiated from CR-propellers exhibits the following specific characteristics: o increased sound pressure levels at higher frequencies, o pronounced azimuthal sound pressure level directivity, o two maxima in the polar directivities of both the high-frequency ha rmonic and the A-weighted levels, o a lower gradient of A-weighted sound pressure levels versus Mach number.
|Document Type:||Conference or Workshop Item (Paper)|
|Additional Information:||LIDO-Berichtsjahr=1990, pages=4,|
|Title:||Azimuthal Noise Characteristics of Contra-Rotating Propellers: Results of a Wind Tunnel Model Test.|
|Page Range:||pp. 471-475|
|Keywords:||Propeller Noise, Counter Rotating Propeller Noise|
|Event Title:||Inter-Noise '90, 13-15 August 1990, Göteborg|
|HGF - Research field:||UNSPECIFIED|
|HGF - Program:||no assignment|
|HGF - Program Themes:||no assignment|
|DLR - Research area:||UNSPECIFIED|
|DLR - Program:||no assignment|
|DLR - Research theme (Project):||L - Turbine Technologies|
|Location:||Köln-Porz , Braunschweig , Göttingen|
|Institutes and Institutions:||Institute of Aerodynamics and Flow Technology > Institut für Entwurfsaerodynamik|
|Deposited By:||elib DLR-Beauftragter|
|Deposited On:||03 Apr 2006|
|Last Modified:||27 Apr 2009 10:04|
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