Aerodynamic and Acoustic Optimization for Fan Flow Deflection

Johnson, Andrew; Xiong, Juntao; Rostamimonjezi, Sara; Liu, Feng; Papamoschou, Dimitri

doi:10.2514/6.2011-1156

Cited by 7 publications

(4 citation statements)

References 14 publications

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“…We also wish to point out that the effects of skin friction have been neglected in our body force modeling. Based on drag measurements on perforated acoustic liners [25] and the results of the present computations, we estimate that skin friction drag is at least one order of magnitude lower than pressure drag for wedge half-angles of 20 deg or higher [26]. Therefore, we expect that skin friction will not significantly affect the aerodynamic performance unless the wedge angle is very small.…”

Section: B Computations Of Simplified Perforationsmentioning

confidence: 59%

Body Force Model for the Aerodynamics of Inclined Perforated Surfaces

et al. 2012

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Section: B Computations Of Simplified Perforationsmentioning

confidence: 59%

Body Force Model for the Aerodynamics of Inclined Perforated Surfaces

et al. 2012

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“…On each array, the distance between the microphones and the nozzle-trailing edge ranges from 0.92 m and 1.23 m. The polar angle coverage is between 60 o and 160 o , where angles less than 90 o are in the upstream direction relative to the nozzle-trailing edge. Details of the jet facility are given elsewhere 12 .…”

Section: Experimental Approachmentioning

confidence: 99%

A Design of Experiments Investigation of Offset Streams for Supersonic Jet Noise Reduction

Henderson¹,

Papamoschou²

2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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An experimental investigation into the noise characteristics of a dual-stream jet with four airfoils inserted in the fan nozzle was conducted. The intent of the airfoils was to deflect the fan stream relative to the core stream and, therefore, impact the development of the secondary potential core and noise radiated in the peak jet-noise direction. The experiments used a full-factorial Design of Experiments (DoE) approach to identify airfoil parameters and parameter interactions impacting noise radiation at two azimuthal microphone array locations corresponding to sideline and flyover aircraft noise measurement points. The parameters studied included airfoil angle-of-attack, airfoil azimuthal location within the fan nozzle, and airfoil axial location relative to the fan-nozzle trailing edge. Jet conditions studied included subsonic and supersonic fan-stream Mach numbers. Heated jet conditions were simulated with a mixture of helium and air to replicate the exhaust velocity and density of hot jets. The introduction of the airfoils was shown to impact noise radiated at aft polar angles and to have no impact on noise radiated at small and broadside polar angles. The airfoils were also found to have no impact on broadband-shock-associated noise. The DoE analysis showed the main effects impacting noise radiation at sideline-azimuthal-viewing angles included airfoil azimuthal angle for the airfoils on the lower side of the jet near the sideline array and airfoil trailing edge distance (with airfoils located at the nozzle trailing edge produced the lowest sound pressure levels). For an array located directly beneath the jet (and on the side of the jet from which the fan stream was deflected), the main effects impacting noise radiation included airfoil angle-of-attack and airfoil azimuthal angle for the airfoils located on the observation side of the jet as well as trailing edge distance. Interaction terms between multiple configuration parameters were shown to have significant impact on the radiated noise. The models were shown to adequately describe the sound-pressure levels obtained for a configuration in the center of the design space indicating the models can be used to navigate the design space.

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“…In another study, A. D. Johnson et al investigated the optimisation of the implementation of fan flow deflection for jet noise suppression from a supersonic turbofan nozzle with a bypass ratio of 2.7 (Johnson et al 2011). They also considered the addition of a porous wedge-shaped fan flow deflector and show FFD increases the EPNL reductions to 5.0 dB and 3.9 dB in the downward and sideline directions, respectively.…”

Section: Fan Flow Deflectormentioning

confidence: 99%

Technologies for Jet Noise Reduction in Turbofan Engines

Gorji-Bandpy

Azimi

2012

Aviation

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Turbofan engines are commonly used for commercial transport due to their advantages of higher performance and lower noise. Jet noise is one of the principal noise sources of turbofan aeroplane engines and remains an acute environmental problem that requires advanced solutions. The ever-increasing demand for quieter engines requires the exploration of alternative techniques that could be used by themselves or in conjunction with existing methods. Significant progress continues to be made with noise reduction for turbofan engines. Analytical and semiempirical models have been developed to investigate the influence of some design tools when they are employed in a multidisciplinary optimisation framework. This paper discusses the major components of jet noise in turbofan engines and presents a review of jet noise reduction technologies.

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Aerodynamic and Acoustic Optimization for Fan Flow Deflection

Cited by 7 publications

References 14 publications

Body Force Model for the Aerodynamics of Inclined Perforated Surfaces

Body Force Model for the Aerodynamics of Inclined Perforated Surfaces

A Design of Experiments Investigation of Offset Streams for Supersonic Jet Noise Reduction

Technologies for Jet Noise Reduction in Turbofan Engines

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