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Effects of Temperature on the Characteristics of Twin Square Jets by Large Eddy Simulations
KTH, School of Engineering Sciences (SCI), Engineering Mechanics.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
2022 (English)In: AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022, American Institute of Aeronautics and Astronautics (AIAA) , 2022, article id AIAA 2022-0681Conference paper, Published paper (Refereed)
Abstract [en]

In this study, we investigate the effects of temperature on the aerodynamic and aeroacoustics characteristics of twin square jets. Implicit Large Eddy Simulations (ILES) are performed for twin jets with a fixed nozzle pressure ratio (NPR) of 3.0 and temperature ratios (TR) of 1.0, 2.0, 4.0, and 7.0. A second-order central scheme is used to resolve acoustic waves, and an artificial dissipation model is applied to capture shock waves and to suppress non-physical oscillations. In addition, the variation of a specific heat ratio as function of temperature is considered under the chemical equilibrium assumption. The numerical results show that the length of potential core is reduced with the increase of temperature due to the enhanced mixing in jet shear layers which can be estimated by turbulent kinetic energy (TKE). Meanwhile, the fluctuations of the transverse velocity show different trends between the cases within the corresponding potential core length, which can be associated with the screeching phenomena of the twin-jet. As temperature increases, the convection Mach number in the jet shear layers is also increased so that the Mach wave is generated for TR of 2.0, 4.0, and 7.0. However, a crackle noise is only observed for TR of 4.0 and 7.0, whose generation is identified by the skewness and kurtosis factors. Relatively low temperature jets (TR of 1.0 and 2.0) are screeching so that peaks are observed in the spectra obtained upstream. On the other hand, broadband component is gradually increased when the jets are heated, and the largest increase is observed at the location exposed to the Mach wave radiation.

Place, publisher, year, edition, pages
American Institute of Aeronautics and Astronautics (AIAA) , 2022. article id AIAA 2022-0681
Keywords [en]
supersonic twin-square jets, temperature effects, aeroacoustics, Large Eddy Simulations
National Category
Aerospace Engineering Fluid Mechanics and Acoustics
Research subject
Aerospace Engineering; Engineering Mechanics
Identifiers
URN: urn:nbn:se:kth:diva-315298DOI: 10.2514/6.2022-0681Scopus ID: 2-s2.0-85123312716OAI: oai:DiVA.org:kth-315298DiVA, id: diva2:1679535
Conference
AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022, San Diego, 3 January 2022 through 7 January 2022
Note

QC 20220819

Part of proceedings: ISBN 978-162410631-6

Available from: 2022-07-01 Created: 2022-07-01 Last updated: 2022-08-19Bibliographically approved

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Ahn, MyeongHwanMihaescu, Mihai

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