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Related Experiment Video

Updated: Jul 10, 2026

Visualization of High Speed Liquid Jet Impaction on a Moving Surface

Visualization of High Speed Liquid Jet Impaction on a Moving Surface

Published on: April 17, 2015

Experiments with rectangular supersonic jets with potential noise reduction technology.

N Scupski¹, J Akatsuka², D K McLaughlin¹

¹Aerospace Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.

The Journal of the Acoustical Society of America

|February 2, 2022

Summary

This summary is machine-generated.

This study investigated supersonic jet noise reduction using fluid inserts and fluid shields in rectangular nozzles. Both methods showed potential for reducing noise radiated from aircraft engines.

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Area of Science:

Aeronautical Engineering
Acoustics
Fluid Dynamics

Background:

Supersonic jets produce significant noise, impacting aircraft operations and environmental concerns.
Rectangular nozzles are relevant for certain aircraft designs, necessitating specific noise reduction strategies.
Previous research has explored various methods for jet noise mitigation, but advanced configurations require further study.

Purpose of the Study:

To evaluate the effectiveness of fluid inserts and fluid shields in reducing noise from supersonic rectangular jets.
To compare the noise reduction capabilities of two distinct active flow control techniques.
To assess the impact of these methods on the acoustic characteristics of overexpanded, shock-containing jets.

Main Methods:

Aeroacoustics experiments were conducted using supersonic jets from rectangular nozzles (aspect ratio 2).
Two noise reduction methods were tested: fluid inserts (distributed air blowing) and fluid shields in dual flow nozzles.
Far-field noise measurements were taken on an arc (approx. 70 equivalent nozzle diameters), with comparisons made on an equal thrust per unit exit area basis.

Main Results:

Both fluid inserts and fluid shields demonstrated noise reduction capabilities compared to a baseline single flow rectangular jet.
The dual flow nozzle with extended bypass flow showed specific benefits for noise radiated to the sides.
Acoustic spectra and directivity patterns were analyzed to quantify the noise reduction performance.

Conclusions:

Fluid inserts and fluid shields are viable methods for supersonic rectangular jet noise reduction.
The dual flow nozzle configuration with side shields is particularly effective for reducing sideline noise.
Further research can optimize these active flow control techniques for practical aerospace applications.