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Effect of impingement surface roughness on the noise from impinging jets
Abhijit Dhamanekar,
Published in American Institute of Physics Inc.
2014
Volume: 26
   
Issue: 3
Abstract
This paper presents extensive acoustic measurements on jets impinging on surfaces of various surface roughness values. Besides surface roughness, the effects of nozzleto-plate spacing distance and nozzle pressure ratio are also investigated. Turbulent mixing noise and tonal noise are explained using far-field wall-jet velocity and impingement region temperature fields. The results demonstrate that roughness of the impingement plate widens the staging region of impingement noise. In general, high speed jet impinging on a rough plate generates less noise compared to a smooth plate. When tones are removed from the spectra, it is found that acoustic power monotonically decreases with increasing surface roughness. Thermal imaging in the stagnation region indicates that whenever tones are present, the temperature at the stagnation region is high. Further, sound pressure directivity pattern of impingement noise is constructed by superimposing a wall-jet and a free jet in the appropriate orientations. © 2014 AIP Publishing LLC.
About the journal
JournalData powered by TypesetPhysics of Fluids
PublisherData powered by TypesetAmerican Institute of Physics Inc.
ISSN10706631
Open AccessNo
Concepts (13)
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    Acoustic noise
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    Infrared imaging
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    Jets
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    Surface roughness
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    ACOUSTIC MEASUREMENTS
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    DIRECTIVITY PATTERN
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    IMPINGEMENT REGIONS
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    IMPINGEMENT SURFACES
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    Nozzle pressure ratio
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    NOZZLE-TO-PLATE SPACING
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    Stagnation regions
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    TURBULENT MIXING NOISE
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    Fighter aircraft