University of Illinois Urbana-Champaign

Resolvent-based framework for jet noise reduction of a low bypass ratio coannular nozzle

Woo, Jaywon

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https://hdl.handle.net/2142/121372

Description

Title
Resolvent-based framework for jet noise reduction of a low bypass ratio coannular nozzle
Author(s)
Woo, Jaywon
Issue Date
2023-07-19
Director of Research (if dissertation) or Advisor (if thesis)
Bodony, Daniel J
Department of Study
Aerospace Engineering
Discipline
Aerospace Engineering
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
M.S.
Degree Level
Thesis
Keyword(s)
  • CFD
  • JNR
  • Computational Aeroacoustics
  • Resolvent Analysis
  • Jet Noise
  • Mixed-streams Nozzle
Abstract
The development of jet noise reduction (JNR) techniques is critical to the integration of supersonic aircraft into commercial travel and transportation. Prescribing JNR methods remains inherently difficult as the reduction of sound is frequently accompanied by a reduction in nozzle performance. This paper utilizes resolvent analysis as a reduced-order modeling technique for the purpose of assessing jet noise reduction concepts on a low bypass ratio coannular nozzle design. An automated framework is built to facilitate the computation of resolvent gain values for varying nozzle conditions and geometries. Specifically, parametric studies are conducted on the mixing duct length and extraction ratio parameters of the nozzle design. RANS mean flow data, used as input for the resolvent computation, are validated against experimental data for the same nozzle configuration. Verification of the linear operator used to define the resolvent is established through comparisons with well-known analytical solutions. Subsequently, the resolvent analysis is verified by comparing sets of singular values and forcing/response modes against corresponding plots reported in the literature. Gain profiles computed for a range of nozzle mixing duct lengths are found to be insensitive to this design parameter. Likewise, gain profiles are also found to be insensitive to variations in extraction ratio at constant thrust. Both of these behaviors are found to be consistent with experimental data suggesting an insubstantial change in noise when varying these nozzle operating parameters. Applying resolvent analysis as a means to assess JNR potential shows promise for comparative design studies, though other nozzle designs and/or operating conditions are needed to positively affirm this.
Graduation Semester
2023-08
Type of Resource
Thesis
Copyright and License Information
Copyright 2023 Jaywon Woo

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