Centreline mixing characteristics of jets from nine differently shaped nozzles

Mi, Jianchun; Nathan, Graham J.; Luxton, R. E.

doi:10.1007/s003480050012

Cited by 145 publications

(84 citation statements)

References 7 publications

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“…1/2 h. For comparison, also shown on the plot are those for a plane jet with the same Reynolds number of Re h = 10 000 ͑and AR= 60͒ from the work of Deo 8 and for a circular jet at Re D = 15 000 from the work of Mi et al 9 Figure 1 demonstrates that, for a rectangular jet with ARജ 30, there are four distinct decay regions of U c . The first is the nondecaying region where U c is constant, the second is the half-power-law decaying region where U c ϳ x −1/2 , then followed by a transition, and the fourth is the inversely linear decaying region where U c ϳ x −1 .…”

Section: Characterization Of Turbulent Jets From High-aspect-ratio Rementioning

confidence: 90%

Characterization of turbulent jets from high-aspect-ratio rectangular nozzles

Deo

Nathan

2005

Physics of Fluids

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Turbulent free jets issuing from rectangular slots with various high aspect ratios (15–120) are characterized. The centerline mean and rms velocities are measured using hot-wire anemometry over a downstream distance of up to 160 slot heights at a slot-height-based Reynolds number of 10 000. Experimental results suggest that a rectangular jet with sufficiently high aspect ratio (>15) may be distinguished between three flow zones: an initial quasi-plane-jet zone, a transition zone, and a final quasi-axisymmetric-jet zone. In the quasi-plane-jet zone, the turbulent velocity field is statistically similar, but not identical, to those of a plane jet.

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Section: Characterization Of Turbulent Jets From High-aspect-ratio Rementioning

confidence: 90%

Characterization of turbulent jets from high-aspect-ratio rectangular nozzles

Deo

Nathan

2005

Physics of Fluids

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“…For the round jet, on the other hand, the centreline decay of the mean velocity is proportional to the inverse of the streamwise distance ( 1 − x ). Mi et al (2000), in another study comparing different types of nozzles, found that the average length of the potential core is higher for circular jets that those issuing from noncircular geometries. This statement implies that there is more entrainment with the surroundings for any non-circular jet than for a round jet (Mi et al, 2000).…”

Section: Resultsmentioning

confidence: 95%

“…Mi et al (2000), in another study comparing different types of nozzles, found that the average length of the potential core is higher for circular jets that those issuing from noncircular geometries. This statement implies that there is more entrainment with the surroundings for any non-circular jet than for a round jet (Mi et al, 2000). Closer to the jet exhaust, the rate of decay is lower for the round jet than its non-circular counterparts.…”

Section: Resultsmentioning

confidence: 95%

Comparison of flow and dispersion properties of free and wall turbulent jets for source dynamics characterisation

Aloysius

Wrobel

2009

Environmental Modelling & Software

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The objective of this paper is to provide an investigation, using large eddy simulations, into the dispersion of aircraft jets in co-flowing take-off conditions. Before carrying out such study, simple turbulent plane free and wall jet simulations are carried out to validate the computational models and to assess the impact of the presence of the solid boundary on the flow and dispersion properties.The current study represents a step towards a better understanding of the source dynamics behind an airplane jet engine during the take-off and landing phases. The information provided from these simulations can be used for future improvements of existing dispersion models. Software availabilitySoftware name: FLUENT 6.

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“…Tsuchiya et al studied the effects of small aspect ratios and various upstream geometries, namely a smooth contraction, orifice plate and 400mm duct and discovered that axis switching occurs in the various experiments. Mi et al, 19,20 Gutmark and Grinstein 21 and Miller et al 22 have also studied the effects on the evolution of the jet plume for a variety of nozzles, (including rectangular nozzles).…”

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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Centreline mixing characteristics of jets from nine differently shaped nozzles

Cited by 145 publications

References 7 publications

Characterization of turbulent jets from high-aspect-ratio rectangular nozzles

Characterization of turbulent jets from high-aspect-ratio rectangular nozzles

Comparison of flow and dispersion properties of free and wall turbulent jets for source dynamics characterisation

CFD Based Study of Unconventional Aeroengine Exhaust Systems

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