Small Business Innovation Research/Small Business Tech Transfer
Numerical and Physical Modeling of the Response of Resonator Liners to Intense Sound and High Speed Grazing Flow, Phase II
Project Description
An aeroacoustic computational code based upon a numerical solution of the full Navier-Stokes equations will be developed to provide a deep understanding of the physical behavior of resonator liners exposed to intense sound and boundary-layer grazing flow. The code computes the entire flow and acoustic field inside the flow duct. The user has the option to choose the flow Mach number, boundary-layer thickness, duct mode of incoming sound, frequency and SPL. For broadband sound, the user has the option to specify an incident noise spectrum. The code is designed to operate at both standard temperatures and very high temperatures. A semi-empirical three-dimensional resonator liner impedance code will developed for resonators also exposed to intense sound and boundary-layer grazing flow. The liner empirical parameters will be calibrated with NASA furnished resonator test data. Because of its simplicity, it can be used to provide realistic liner geometries for sound propagation codes that are used in both NASA and industry to determine optimum wall impedances to control excessive sound generated in jet engines and other flow duct environments.
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Anticipated Benefits
An aeroacoustic computer code will be developed capable of predicting the impedance of liners exposed to intense sound, high subsonic grazing flows and at high temperatures. This will provide an essential tool for the aircraft engine acoustic designers to understand how resonators behave in harsh engine environments. A three dimensional liner impedance model will be developed and mated to a flow duct sound propagation code to provide the designer of HVAC centrifugal and axial with the necessary tools to design highly efficient sound absorbing HVAC centrifugal and axial products. This technology is capable of being ported, for example, to manufacturers of space heaters and other products requiring quiet airflows. An aeroacoustic computer code will be developed capable of predicting the impedance of liners exposed to intense sound, high subsonic grazing flows and at high temperatures. This will provide an essential tool for the aircraft engine acoustic designers to understand how resonators behave in harsh engine environments. A 3-D liner impedance model will be developed capable of determining the incident sound pressure far-field face-plate distances from resonator orifices. This represents an initial step in improving our understanding of how to effectively use the Dean Two-Microphone impedance measurement method. This is especially important because the Dean method is one of the current benchmark standards used to measure the effects of grazing flow and SPL on the impedance of cavity-backed liners.
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Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
| Hersh Acoustical Engineering, Inc. | Lead Organization |
Industry
Women-Owned Small Business (WOSB)
|
Calabasas, California |
Langley Research Center
(LaRC)
|
Supporting Organization | NASA Center | Hampton, Virginia |
Primary U.S. Work Locations
-
California
-
Virginia
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This is a historic project that was completed before the creation of TechPort on October 1, 2012. Available data has been included. This record may contain less data than currently active projects.