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 Copy

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

Handle URL

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

Copyright and License Information

Copyright 2023 Jaywon Woo

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