kth.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Flow and Near-field Pressure Fluctuations of Twin Square Jets
KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics.ORCID iD: 0000-0002-9054-8832
KTH, School of Engineering Sciences (SCI), Engineering Mechanics, Fluid Mechanics and Engineering Acoustics.ORCID iD: 0000-0001-7330-6965
2021 (English)In: AIAA Propulsion and Energy Forum, 2021, American Institute of Aeronautics and Astronautics Inc, AIAA , 2021Conference paper, Published paper (Refereed)
Abstract [en]

We aim to investigate the aerodynamic and acoustics characteristics of a twin square jet using an implicit Large Eddy Simulation (ILES). A screeching cold jet condition, a nozzle pressure ratio (NPR) of 3.0, is considered to simulate a coupled twin-jet. A second-order central scheme with a modified version of Jameson’s artificial dissipation is adopted to damp numerical oscillations and to mimic the effect of small-scale turbulence without an explicit subgrid-scale (SGS) model. Numerical results show that the overall trends of time-averaged streamwise velocity profiles are similar to the experimental data, with the largest differences observed at locations associated with the presence of the shock-cell structures. A detailed investigation of the flow fluctuations in jet shear layers is performed. The amplitude of the velocity fluctuations is highly dependent on the location of the shear layers with respect to the twin-jet configuration (upper, lateral, or inner). The coupling mode of twin jets associated with the screech tone is determined as a symmetrical flapping mode be a two-points spacetime cross-correlation analysis. The overall trends of near-field pressure fluctuation spectra by LES agree well with the experimental results in both upstream and downstream regions. Near-field pressure fluctuation spectra by ILES agree well with the experimentally obtained spectra at different locations in the nozzle exit plane as well as at several downstream locations in the near-field acoustic region. The highest screech tone is observed at the inter-nozzle region where superposition of in-phase waves and standing waves are found. Fourier phase and amplitude fields at the fundamental frequency also confirm the symmetrical flapping mode of the twin jets by showing in-phase relations of hydrodynamic/acoustic waves and noise directivities. 

Place, publisher, year, edition, pages
American Institute of Aeronautics and Astronautics Inc, AIAA , 2021.
Keywords [en]
Aeroacoustics, Fourier series, Large eddy simulation, Nozzles, Shear flow, Aerodynamic characteristics, Fluctuation spectrum, Implicit large Eddy simulations, In-phase, Near fields, Pressure fluctuation, Screech tones, Shear layer, Square jets, Twin-jets, Location
National Category
Fluid Mechanics and Acoustics
Identifiers
URN: urn:nbn:se:kth:diva-316400DOI: 10.2514/6.2021-3554Scopus ID: 2-s2.0-85123278533OAI: oai:DiVA.org:kth-316400DiVA, id: diva2:1687806
Conference
AIAA Propulsion and Energy Forum, 2021, Virtual/Online, 9-11 August 2021
Note

Part of proceedings: ISBN 978-1-62410-611-8

QC 20220816

Available from: 2022-08-16 Created: 2022-08-16 Last updated: 2022-08-16Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textScopus

Authority records

Ahn, MyeonghwanMihaescu, Mihai

Search in DiVA

By author/editor
Ahn, MyeonghwanMihaescu, Mihai
By organisation
Fluid Mechanics and Engineering Acoustics
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 46 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf