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Measurement of the noise generation at the trailing edge of porous airfoils
Owls are commonly known for their quiet flight, enabled by three adaptions of their wings and plumage: leading edge serrations, trailing edge fringes and a soft and elastic downy upper surface of theExpand
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Trailing edge noise of partially porous airfoils
The use of porous trailing edges is one possible approach to reduce airfoil trailing edge noise. Past experiments on fully porous airfoil models showed that a noticeable noise reduction can beExpand
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A fast signal subspace approach for the determination of absolute levels from phased microphone array measurements
Phased microphone arrays are used in a variety of applications for the estimation of acoustic source location and spectra. The popular conventional delay-and-sum beamforming methods used with suchExpand
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Application of a Beamforming Technique to the Measurement of Airfoil Leading Edge Noise
The present paper describes the use of microphone array technology and beamforming algorithms for the measurement and analysis of noise generated by the interaction of a turbulent flow with theExpand
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Microphone array method for the characterization of rotating sound sources in axial fans
Methods based on microphone array measurements provide a powerful tool for determining the location and magnitude of acoustic sources. For stationary sources, sophisticated algorithms working in theExpand
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Porous Airfoils: Noise Reduction and Boundary Layer Effects
The present paper describes acoustic and hot–wire measurements that were done in the aeroacoustic wind tunnel at the Brandenburg University of Technology Cottbus on various SD7003–type airfoils madeExpand
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Silent Owl Flight: Bird Flyover Noise Measurements
Mostgeneraofowls(Strigiformes)havetheabilityto flysilently.Themechanismsofthesilent flightoftheowlhave been the subject of scientific interest for many decades. The results from studies in the pastExpand
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Three-Dimensional Acoustic Source Mapping with Different Beamforming Steering Vector Formulations
Acoustic source mapping techniques using acoustic sensor arrays and delay-and-sum beamforming techniques suffer from bad spatial resolution at low-aperture-based Helmholtz numbers. This is especiallyExpand
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Silent owl flight: The effect of the leading edge comb
The feathers of owls possess three adaptations that are held responsible for their quiet flight. These are a comb-like structure at the leading edge of the wing, fringes at the trailing edge, and aExpand
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Silent Owl Flight: Acoustic Wind Tunnel Measurements on Prepared Wings
wings are characterized in the study as technical airfoils in terms of their acoustic and aerodynamic performance. The experiments took place in an aeroacoustic open jet wind tunnel using microphoneExpand
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