Large-Eddy Simulations of Perfectly Expanded Supersonic Jets Using an Unstructured Solver

Mendez, Simon; Shoeybi, Mohammad; Sharma, Arjun; Ham, Frank; Lele, Sanjiva K.; Moin, Parviz

doi:10.2514/1.j051211

Cited by 49 publications

(72 citation statements)

References 51 publications

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“…Besides obtaining good agreement with available data on round nozzles for various operating conditions, they also reported the ability to compute the jet noise sensitivity to nozzle geometry change using emulated boundary conditions (see [51] for in-depth assessment). LES calculations directly including the nozzle geometry, with chevrons, internal mixing, etc., using an unstructured grid, were achieved more recently using a finite volume method [25,[52][53][54][55]. Although finite volume methods are nominally only second-order accurate, excellent agreement with flow and both near-and far-field acoustic measurements was achieved with approximately 40-70 M control volumes [56].…”

Section: (A) Computational Algorithmsmentioning

confidence: 99%

A second golden age of aeroacoustics?

Lele

Nichols

2014

Phil. Trans. R. Soc. A.

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In 1992, Sir James Lighthill foresaw the dawn of a second golden age in aeroacoustics enabled by computer simulations (Hardin JC, Hussaini MY (eds) 1993 Computational aeroacoustics, New York, NY: Springer (doi:10.1007). This review traces the progress in large-scale computations to resolve the noise-source processes and the methods devised to predict the far-field radiated sound using this information. Keeping focus on aviation-related noise sources a brief account of the progress in simulations of jet noise, fan noise and airframe noise is given highlighting the key technical issues and challenges. The complex geometry of nozzle elements and airframe components as well as the high Reynolds number of target applications require careful assessment of the discretization algorithms on unstructured grids and modelling compromises. High-fidelity simulations with 200-500 million points are not uncommon today and are used to improve scientific understanding of the noise generation process in specific situations. We attempt to discern where the future might take us, especially if exascale computing becomes a reality in 10 years. A pressing question in this context concerns the role of modelling in the coming era. While the sheer scale of the data generated by large-scale simulations will require new methods for data analysis and data visualization, it is our view that suitable theoretical formulations and reduced models will be even more important in future.

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Section: (A) Computational Algorithmsmentioning

confidence: 99%

A second golden age of aeroacoustics?

Lele

Nichols

2014

Phil. Trans. R. Soc. A.

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“…Typically studies using LES have been constrained to axi-symmetric nozzles, Mendez et al, 23 however rectangular nozzles are beginning to be investigated as well, Nichols et al 24 These studies have shown a very good agreement between the experimental data and the LES predictions.…”

Section: 13mentioning

confidence: 99%

CFD Based Study of Unconventional Aeroengine Exhaust Systems

Coates

Page

2012

30th AIAA Applied Aerodynamics Conference

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The effect of upstream duct curvature on the exhaust plume of a jet engine is currently undocumented. Here, three different upstream curvatures are simulated using CFD to investigate the effect of upstream duct curvature on the over-expanded exhaust plume emanating from a rectangular nozzle of aspect ratio 5.8:1 at a nozzle pressure ratio of 2.5 and Reynolds number of 7.61 × 10 5 . Due to the lack of available experimental data for curved ducts connected to high speed jets, the initial work was to validate the methodology for separate S-bend and rectangular nozzle high speed jet cases. These showed that RANS methods were poor for predicting secondary flows in the S-bend and for predicting mixing and potential core length in the rectangular jet. However, LES did show significant improvements for the rectangular jet and correctly predicts the shear layer mixing. Calculations were carried out using an unstructured, median-dual CFD solver with predominantly hexahedral elements containing approximately 65.5−67.5 million nodes. For the combined S-bend and nozzle cases it was seen that increasing upstream duct curvature reduces the potential core length and increases losses in the upstream duct. Transverse total pressure gradients were also observed at the nozzle exit plane in both k-ǫ and WALE LES turbulence models, however to a significantly smaller degree in the latter. The upstream duct curvature was also seen to have an impact on the shock cell development, altering both number and location.

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“…[13][14][15] Other techniques have also been employed. To reduce simulation costs, it is common for researchers to utilize thin laminar BLs, [16][17][18][19][20] slip wall boundary conditions, [21][22][23][24] and mean flow conditions in the near-wall region (i.e., RANS/LES hybrid methods) 25,26 The method used in ref. 27 is unclear.…”

Section: Introductionmentioning

confidence: 99%