Supersonic impinging jet noise reduction using a hybrid control technique

Wiley, Alex; Kumar, Rajan

doi:10.1016/j.jsv.2015.03.024

Cited by 3 publications

(4 citation statements)

References 29 publications

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“…The absence of tones in the case of a supersonic jet impinging on the porous plate is contradictory to the observation of Wiley and Kumar. 45 However, the plates used in the present study are completely different from theirs. While the porous plates used in the present study have interconnectivity of pores, Wiley and Kumar 45 used perforated plates (through holes across the plate without any interconnectivity).…”

Section: Spectral Analysismentioning

confidence: 87%

“…45 However, the plates used in the present study are completely different from theirs. While the porous plates used in the present study have interconnectivity of pores, Wiley and Kumar 45 used perforated plates (through holes across the plate without any interconnectivity). Therefore, instead of using perforated plates, it is better to use porous plates with interconnectivity, as shown in Figure 3.…”

Section: Spectral Analysismentioning

confidence: 87%

“…The impinging surface used in the present work is quite different from the perforated plates used by other researchers. 44,45 That is, in most cases isotropic porous media is used whereas, in the present work, an anisotropic porous media is used. Further, their measurement is limited to near-field at one or two points.…”

Section: Introduction and State Of The Artmentioning

confidence: 99%

“…43 Recently, Karthikeyan and Venkatakrishnan 44 observed that replacing the solid launch platform with a perforated one leads to lower noise levels than the solid one but still higher than the case where the launch platform is absent. Wiley and Kumar 45 studied the impingement of a supersonic under-expanded jet on plates of different permeability/perforations. They found that the acoustic intensity can be reduced by making the obstacle permeable.…”

Section: Introduction and State Of The Artmentioning

confidence: 99%

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Acoustic characteristics of jets impinging on permeable plates

Dhamanekar,

Srinivasan

2023

International Journal of Aeroacoustics

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This article explores the acoustic characteristics and the relevant flow features of jets impinging on permeable plates. Noise generated due to the interaction of the jet with permeable plates is compared with jets impinging on an impermeable plate and the corresponding free jet. This study systematically measures various parameters, including pore size, porosity, and pressure drop, to precisely quantify the permeability of the plates using the Forchheimer equation. The focus is on investigating the impact of permeability on noise reduction. An acoustic study is performed by carrying out blow-up and blow-down tests to find the effect of permeability at different nozzle pressure ratios and different nozzle-plate spacings. An extensive directivity study is conducted to find the directionality of acoustic emissions and calculate acoustic power. It is found that the overall sound pressure level is lower for the jets impinging on the permeable plates compared to the impermeable plates in subsonic cases. It is also observed that the insertion of the permeable plates in supersonic jets generates less noise compared to the corresponding free jet. It is found that most of the tones are absent in the case of permeable plates for supersonic jets, whereas the tones are present with lesser amplitude compared to jets impinging on impermeable plates for subsonic and transonic jets. Finally, flow measurement and flow visualization studies are carried out to understand the flow physics responsible for the noise variance. This study illuminates that the passage of flow through the porous plate results in the reduction of wall-jet velocities, thereby suppressing the turbulent mixing noise. The absence of shock oscillations in front of the permeable plate is identified as the cause of the mitigation of impinging tones.

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Section: Spectral Analysismentioning

confidence: 87%

Section: Spectral Analysismentioning

confidence: 87%

Section: Introduction and State Of The Artmentioning

confidence: 99%

Section: Introduction and State Of The Artmentioning

confidence: 99%

See 2 more Smart Citations

Acoustic characteristics of jets impinging on permeable plates

Dhamanekar,

Srinivasan

2023

International Journal of Aeroacoustics

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A review of impinging jets during rocket launching

Han

Gao

Lee

2019

Progress in Aerospace Sciences

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Tonal Noise Suppression of an Underexpanded Orifice Jet Upon Impingement Over Corrugated Geometries

Sarangi

Srinivasan

2022

Journal of Vibration and Acoustics

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The current study investigates the noise generation of an orifice jet upon impingement over different corrugated geometries for different nozzle pressure ratios. Semi-circular corrugations of different pitch lengths are considered for this study. A comparison of corrugated geometries is made with the flat plate. A standoff distance of 3.5 times jet diameter is considered. Several tones and their harmonics of the feedback loops established between the orifice exit and the plates are analyzed. The far-field acoustic spectra show that the corrugated geometries emit less noise at subsonic speed compared to supersonic speed. A reduction of overall sound pressure level (OASPL) up to a range of 3 dB to 8 dB is observed for the corrugated plate compared to the base plate at the subsonic range. The tonal noise is reduced for the corrugated geometries at all NPRs. The wavelength of the primary tones is compared with the pitch length of semi-circular corrugations. This indicates that semi- circular corrugations reduce the wavelength of fundamental tones and increase the time required to complete the feedback loop. Schlieren images show the presence of the acoustic feedback loop and standing waves near the impingement region for the flat plate. The flow field in between the semi-circular corrugations is analyzed by solving the large eddy simulation. The directivity study shows a reduction in OASPL value at the upstream direction at NPR 4 and 4.8 for the corrugated geometries.

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Supersonic impinging jet noise reduction using a hybrid control technique

Cited by 3 publications

References 29 publications

Acoustic characteristics of jets impinging on permeable plates

Acoustic characteristics of jets impinging on permeable plates

A review of impinging jets during rocket launching

Tonal Noise Suppression of an Underexpanded Orifice Jet Upon Impingement Over Corrugated Geometries

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