Simultaneous Measurement of Flow Fluctuations and Near-Field Pressure in a Subsonic Jet

2009 ◽  
Author(s):  
Jeff Kastner ◽  
Daniel Cuppoletti ◽  
Ephraim Gutmark ◽  
Andrew Fahrland ◽  
Jay Jeffries ◽  
...  
Keyword(s):  
Simultaneous Measurement ◽  
Near Field ◽  
Flow Fluctuations ◽  
Subsonic Jet

Simultaneous Measurement of Electric and Magnetic Fields With a Dual Probe for Efficient Near-Field Scanning

2019 ◽  
Vol 67 (4) ◽  
pp. 2859-2864 ◽  
Author(s):  
Weiheng Shao ◽  
Wenxiao Fang ◽  
Yun Huang ◽  
Guangwei Li ◽  
Lei Wang ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Simultaneous Measurement ◽  
Near Field ◽  
Electric And Magnetic Fields ◽  
Near Field Scanning ◽  
Dual Probe

Dynamics of an impinging jet. Part 2. The noise generation

1982 ◽  
Vol 116 ◽  
pp. 379-391 ◽  
Author(s):  
Nagy S. Nosseir ◽  
Chih-Ming Ho
Keyword(s):  
Coherent Structures ◽  
Near Field ◽  
Pressure Fluctuations ◽  
Aerodynamic Noise ◽  
Far Field ◽  
Noise Generation ◽  
Physical Mechanisms ◽  
Field Noise ◽  
Subsonic Jet ◽  
Jet Axis

The aerodynamic noise generated by a subsonic jet impinging on a flat plate is studied from measurements of near-field and surface-pressure fluctuations. The far-field noise measured at 90° to the jet axis is found to be generated by two different physical mechanisms. One mechanism is the impinging of the large coherent structures on the plate, and the other is associated with the initial instability of the shear layer. These two sources of noise radiate to the far field via different acoustical paths.

scholarly journals Near-field Wavepackets and the Far-field Sound of a Subsonic Jet

2013 ◽  
Author(s):  
David E. Breakey ◽  
Peter Jordan ◽  
Andre Cavalieri ◽  
Olivier Léon
Keyword(s):  
Near Field ◽  
Far Field ◽  
Field Sound ◽  
Subsonic Jet

Nonlinear interaction model of subsonic jet noise

2008 ◽  
Vol 366 (1876) ◽  
pp. 2745-2760 ◽  
Author(s):  
Neil D Sandham ◽  
Adriana M Salgado
Keyword(s):  
Near Field ◽  
Sound Radiation ◽  
Jet Noise ◽  
Interaction Model ◽  
Simplified Model ◽  
Nonlinear Interactions ◽  
Radiation Characteristics ◽  
Instability Modes ◽  
Field Sound ◽  
Subsonic Jet

Noise generation in a subsonic round jet is studied by a simplified model, in which nonlinear interactions of spatially evolving instability modes lead to the radiation of sound. The spatial mode evolution is computed using linear parabolized stability equations. Nonlinear interactions are found on a mode-by-mode basis and the sound radiation characteristics are determined by solution of the Lilley–Goldstein equation. Since mode interactions are computed explicitly, it is possible to find their relative importance for sound radiation. The method is applied to a single stream jet for which experimental data are available. The model gives Strouhal numbers of 0.45 for the most amplified waves in the jet and 0.19 for the dominant sound radiation. While in near field axisymmetric and the first azimuthal modes are both important, far-field sound is predominantly axisymmetric. These results are in close correspondence with experiment, suggesting that the simplified model is capturing at least some of the important mechanisms of subsonic jet noise.

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