Far-Field Acoustic Measurements of Dual Impinging Scale Model Jets

Myers, Leighton M.; Kuo, Ching-Wen; McLaughlin, Dennis K.

doi:10.2514/6.2014-3200

Cited by 11 publications

(2 citation statements)

References 14 publications

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“…Both graphs show a distinct tone present in the velocity spectra. This tone shows excellent agreement with the acoustic measurements of Myers et al 54 Both measurements indicate a tone frequency of 12.7 kHz. The amplitude of this tone appears greatest close to the jet centerline near the approximate location of the stand-off shock (y=D r ¼ 0:5) ( Figure 14(a)).…”

Section: Impinging Jet Velocity Spectrasupporting

confidence: 87%

“…For a lift plate stand-off of 5 D r , spectra have been calculated from axial measurements in the impingement region and radial measurements in the wall jet shear layer. Experimental parameters correspond to those used by Myers et al 54 for impinging jet acoustic measurements. A 20 dB impingement tone was observed in the acoustic data.…”

Section: Impinging Jet Velocity Spectramentioning

confidence: 99%

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Unsteady velocity measurements of model-scale supersonic exhaust jets in military-relevant configurations

Hromisin

Powers

Myers

2018

International Journal of Aeroacoustics

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Of the utmost importance is the need to better understand the high temperature, high velocity flow fields generated by military tactical aircraft during ''run up'' and takeoff that gives rise to extremely hazardous conditions for personnel and equipment within the vicinity of the aircraft. The present study aims to fill the need for high frequency, two velocity component measurements throughout the flow fields produced by university-scale supersonic jets exhausting from nozzles in configurations relevant to practical, full-scale application. Specifically, this work focuses on studying the supersonic jets operating in two basic configurations: horizontal, free jets and jets impinging normal to a ground plane reminiscent of current short-takeoff and vertical landing aircraft. Experiments are conducted at nozzle operating conditions similar to those of full-scale aircraft. Both mean velocities and turbulence components are measured in both flow fields using a laser Doppler velocimeter. Axial components of the mean flow and turbulence are measured in the free jet. In the single impinging jet flow field two-component mean velocity and turbulence components are measured in the jet plume, impingement region, and outwash flow. Free jet velocity measurements show good consistency with 50% increase in jet Reynolds number. Turbulence intensities up to 15% of the mean jet exit velocity are observed at the nozzle exit plane. Laser Doppler measurements in the outwash of an impinging jet show turbulent fluctuations produce unsteady velocities well above the mean value. Two-component impinging jet unsteady velocity spectra show a distinct peak at the same frequency as the impingement tone observed in prior impinging jet acoustic field measurements.

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Section: Impinging Jet Velocity Spectrasupporting

confidence: 87%

Section: Impinging Jet Velocity Spectramentioning

confidence: 99%

Unsteady velocity measurements of model-scale supersonic exhaust jets in military-relevant configurations

Hromisin

Powers

Myers

2018

International Journal of Aeroacoustics

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Effect of relative jet momentum in supersonic dual impinging jets

et al. 2022

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Effect of Relative Jet Temperature in Supersonic Dual-Impinging Jets

2023

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Short takeoff and vertical landing aircraft configurations involve multiple jets that impinge onto the deck surface in tandem and lead to several adverse effects. This study reports on the experimental characterization of supersonic dual-impinging jets by systematically varying their relative jet temperature. A sonic converging and Mach 1.5 converging–diverging (CD) nozzles are employed. The expansion ratio of the converging nozzle is maintained at 0.96, 1.19, and 1.59, and the CD nozzle is operated at a fixed nozzle pressure ratio of 3. The temperature ratio of the jet from the CD nozzle is varied from 1.0, 1.3, and 1.7. For a fixed momentum of the jet pair, an increase in jet temperature intensified the nearfield noise and unsteadiness on the impingement surface. At short impingement heights, resonance in the heated jet was the primary source of unsteadiness. At a fixed impingement height, an increase in jet temperature led to a systematic increase in tonal frequency, while jet instability mode shapes were retained. Furthermore, the mean flowfield of sonic jet and fountain regions remain unaffected, and an increase in supersonic jet velocity is observed. This is also accompanied by an increase in unsteadiness in the fountain upwash.

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Far-Field Acoustic Measurements of Dual Impinging Scale Model Jets

Cited by 11 publications

References 14 publications

Unsteady velocity measurements of model-scale supersonic exhaust jets in military-relevant configurations

Unsteady velocity measurements of model-scale supersonic exhaust jets in military-relevant configurations

Effect of relative jet momentum in supersonic dual impinging jets

Effect of Relative Jet Temperature in Supersonic Dual-Impinging Jets

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