Abstract
The noise generation mechanisms for four directly impinging supersonic jets are investigated employing implicit large eddy simulations with a higher-order accurate weighted essentially non-oscillatory shock-capturing scheme. Impinging jet devices are often used as an experimental apparatus to emulate a broadband noise source. Although such devices have been used in many experiments, a detailed investigation of the noise generation mechanisms has not been conducted before. Thus, the underlying physical mechanisms that are responsible for the generation of sound waves are not well understood. The flow field is highly complex and contains a wide range of temporal and spatial scales relevant for noise generation. Proper orthogonal decomposition of the flow field is utilized to characterize the unsteady nature of the flow field involving unsteady shock oscillations, large coherent turbulent flow structures, and the sporadic appearance of vortex tubes in the center of the impingement region. The causality method based on Lighthill’s acoustic analogy is applied to link fluctuations of flow quantities inside the source region to the acoustic pressure in the far field. It will be demonstrated that the entropy fluctuation term in the Lighthill’s stress tensor plays a vital role in the noise generation process. Consequently, the understanding of the noise generation mechanisms is employed to develop a reduced-order linear acoustic model of the four-jet impingement device. Finally, three linear acoustic FJID models are used as broadband noise sources inside an engine nacelle and the acoustic scattering results are validated against far-field acoustic experimental data.
Original language | English |
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Title of host publication | 21st AIAA/CEAS Aeroacoustics Conference |
DOIs | |
State | Published - 2016 |
Event | 21st AIAA/CEAS Aeroacoustics Conference, 2015 - Dallas, United States Duration: Jun 22 2015 → Jun 26 2015 |
Publication series
Name | 21st AIAA/CEAS Aeroacoustics Conference |
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Conference
Conference | 21st AIAA/CEAS Aeroacoustics Conference, 2015 |
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Country/Territory | United States |
City | Dallas |
Period | 6/22/15 → 6/26/15 |
Bibliographical note
Publisher Copyright:© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.
ASJC Scopus subject areas
- Aerospace Engineering
- Electrical and Electronic Engineering