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Effects of Temperat...
Effects of Temperature on the Characteristics of Twin Square Jets by Large Eddy Simulations
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- Ahn, MyeongHwan (författare)
- KTH,Teknisk mekanik
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- Mihaescu, Mihai, Professor, 1976- (författare)
- KTH,Strömningsmekanik och Teknisk Akustik
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(creator_code:org_t)
- 2022-12-29
- 2022
- Engelska.
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Ingår i: AIAA Science and Technology Forum and Exposition, AIAA SciTech Forum 2022. - Reston, Virginia : American Institute of Aeronautics and Astronautics (AIAA).
- Relaterad länk:
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https://urn.kb.se/re...
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visa fler...
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https://doi.org/10.2...
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visa färre...
Abstract
Ämnesord
Stäng
- 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.
Ämnesord
- TEKNIK OCH TEKNOLOGIER -- Maskinteknik -- Rymd- och flygteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Mechanical Engineering -- Aerospace Engineering (hsv//eng)
- TEKNIK OCH TEKNOLOGIER -- Maskinteknik -- Strömningsmekanik och akustik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Mechanical Engineering -- Fluid Mechanics and Acoustics (hsv//eng)
Nyckelord
- supersonic twin-square jets
- temperature effects
- aeroacoustics
- Large Eddy Simulations
- Aerospace Engineering
- Flyg- och rymdteknik
- Teknisk mekanik
- Engineering Mechanics
Publikations- och innehållstyp
- ref (ämneskategori)
- kon (ämneskategori)