An Improved Correlation for the Broadband Noise of High-speed Fans

Ginder, R. B.; Newby, D. R.

doi:10.2514/3.58864

Cited by 20 publications

(3 citation statements)

References 6 publications

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“…The third term is from Ginder and Newby [19] and considers the effect of tip speed on fan noise. The fourth term is a simple model for attenuation due to acoustic treatment, based on results from Law and Dowling [20].…”

Section: Fan-noise Modelmentioning

confidence: 99%

Assessment of Technologies for the Silent Aircraft Initiative

Hall

Schwartz

Hileman

2009

Journal of Propulsion and Power

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The Silent Aircraft Initiative produced an aircraft design that combined many new and novel technologies to give a solution that was predicted to be fuel-efficient as well as extremely quiet. The study presented in this paper seeks to assess the benefits and penalties of each of the proposed technologies. A method has been developed that estimates the overall change in fuel consumption and engine noise caused by modifications to an aircraft design. The method sizes a propulsion system for a specified design and determines adjustments to the cruise performance based on changes in the engine components, the installation system, and system weight. The offdesign performance is also calculated so that the noise can be estimated. The method has been applied to show what contribution each silent aircraft technology made to the overall goal of the project. It also shows the tradeoffs between noise and fuel consumption for various technologies and indicates that there are configurations that can achieve both lower fuel burn and lower engine noise. The method has been used to identify a low-risk configuration of the silent aircraft, for which a new design is presented.

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Section: Fan-noise Modelmentioning

confidence: 99%

Assessment of Technologies for the Silent Aircraft Initiative

Hall

Schwartz

Hileman

2009

Journal of Propulsion and Power

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“…10. Fan blade suction surface flow separation and interaction with the trailing edge, blade tip interaction with the casing boundary layer and rotor wake turbulence (midspan or tip) interaction with the stator are candidate mechanisms although the latter seems to be discounted by rotor alone experiments (28) While the multiple pure tone (MPT) generation mechanism is clearly associated with the rotor leading edge shocks and their blade-to-blade nonuniformity, quantitative descriptions of the source are lacking. Two aspects of the process have been investigated in connection with concepts to reduce this strong inlet source at takeoff fan speeds.…”

Section: Mechanism Identificationmentioning

confidence: 99%

Aircraft Turbofan Noise

Groeneweg

Rice

1983

Volume 5: Ceramics; Structures and Dynamics; Controls, Diagnostics and Instrumentation; Education; Process Industries

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Recent advances in the understanding of turbofan noise generation and suppression in aircraft engines are reviewed with particular emphasis on NASA research. The review addresses each link in the chain of physical processes which connect unsteady flow interactions with fan blades to far field noise. Mechanism identification and description, duct propagation, radiation and acoustic suppression are discussed. Recent advances in the experimental technique of fan inflow control assure that in-flight generation mechanisms are not ma.,ked by extraneous sources in static tests. Rotor blade surface pressure and wake velocity measurements aid the determination of the types and strengths of the generation mechanisms. Approaches to predicting or measuring acoustic mode content, optimizing treatment impedance to maximize attenuation, translating impedance into porous wall structure and interpreting far field directivity patterns are illustrated by comparisons of analytical and experimental results. A persistent theme of the review is the interdependence of source and acoustic treatment design to minimize far field noise. Areas requiring further research are discussed and the relevance of aircraft turbofan results to quieting other turbomachinery installations is addressed.

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“…Ginder and Newby (ref. 15) considered forward arc acoustic results for several fans statically tested in an anechoic facility with inflow control as well as the QF-6 results of reference 11. They concluded that the fan stage broadband noise levels were related to changes in the rotor leading edge incidence, which changed with the stage nozzle area, or flow.…”

Section: Introductionmentioning

confidence: 99%