Aeroacoustics

Aeroacoustics focuses on the study of noise produced by turbulent fluid motion in complex flows.

Aeroacoustics sits at the intersection between physical acoustics and the general study of turbulence.

This specialized field focuses on the study of noise produced by turbulent fluid motion in complex flows and has wide-ranging applications, from military initiatives such as noise reduction in jet propulsion and analysis of noise from ballistic missile launches, to civilian uses including drone noise assessment and evaluation of acoustic interactions in combustion and chemical processes. This research not only enhances noise management strategies but also broadens our understanding of sound dynamics in various environments.

Our current research efforts include:

High-Speed Two-Phase Flows

Studying the dynamics of particle-laden high-speed flows.

Aero-Thermo-Dynamics

Studies on the aero-thermo-dynamics in excited and/or perturbed high-speed boundary layers.

Shockwave Boundary-Layer Interaction

Dynamics of turbulence and shock interactions in high-speed boundary layers.

Turbulence Dynamics in Transient Flows

Decomposition, analysis, and characterization of turbulence induced by shock-driven transients.

AeroAcoustics

High-fidelity measurements and dynamical system analysis of aeroacoustic phenomenon.

"I find turbulence and fluid mechanics simply elegant, beautiful and fun." —Nathan Murray, Director, NCPA

Our Work in Aeroacoustics

Research involving turbulence interactions with fluid media and its boundaries.

Quieting the Roar of Supersonic Jets

NCPA developed a unique but simple solution to reduce the extreme noise from supersonic jets like those on military aircraft. The solution originally patented by J. M. Seiner (U.S. Patents 7240493B2 and 7475550B2) features a series of lobe-shaped contoured panels used to form the exhaust nozzle for the jet engine. Working in collaboration with Combustion Research and Flow Technology, Inc., the aeroacoustics research group led by Dr. Nathan Murray worked to optimize the shape of the contoured panels. The culmination of the multi-year, Navy funded effort to maximize the benefit of Seiner's original concept concluded with a successful 3 dB reduction (about 30% lower) of the noise levels using a simple, single-part, retro-fit design with less than 1% impact to thrust and no impact to the aircraft systems or flight-deck operation. The research also developed tools for multi-objective aeroacoustic design optimization that have been used for many other applications.
Reducing Jet Noise

Recent Research From Our Team

Contoured Insert Jet Noise Reduction Concept Applied to a Lab-Scale Representation of an Afterburning Supersonic Jet

This paper presents a concept for reducing jet noise by applying a contoured insert to a lab-scale representation of an afterburning supersonic jet. The study explores how the contoured insert influences the acoustic properties of the jet, aiming to lower noise levels associated with afterburning in high-speed aircraft.

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Surface Pressure Based Flow Field Estimation: Comparison of LSE and Machine Learning Algorithms

This study compares traditional linear stochastic estimation (LSE) with support vector machine (SVM) algorithms for reconstructing the unsteady behavior of a laminar separation bubble (LSB) on a NACA 0018 airfoil. The algorithms were trained using time-resolved velocity field and surface pressure measurements. Results showed that both LSE and SVM methods effectively captured the development of dominant flow structures, with comparable performance across the different approaches.

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A Proper Framework for Studying Noise From Jets with Non-Compact Sources

This study quantitatively assesses the acoustic field produced by a laboratory-scale heated jet with high Mach numbers, using microphone arrays to map the sound pressure levels across the jet's field. The analysis identifies a dominant sound lobe along the expected emission path for such supersonic flows. Further frequency-based analysis reveals the location, strength, convection velocity, and propagation angle of various noise sources along the jet's axis.

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Mississippi Aerospace and Defense Symposium

We had the privilege of sponsoring and co-hosting the 2024 Mississippi Aerospace and Defense Symposium (MADS), organized by the Aerospace and Defense Alliance of Mississippi (ADAM). This annual event, co-hosted with Mississippi Enterprise for Technology, showcases business opportunities in the aerospace and defense sectors. MADS brings together industry leaders, academic institutions, government officials, and economic developers to foster collaboration and innovation across the industry.