Experiments on a Turbulent Jet in a Cross Flow

Kamotani, Y.; Greber, Isaac

doi:10.2514/3.50386

Cited by 447 publications

(137 citation statements)

References 2 publications

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“…In each case, only the deflected jet is observed, and no smoke is seen in the wake region. Furthermore in Kamotani & Greber's (1972) study of a heated transverse jet, temperature contours showed that the excess heat downstream of the orifice was confined to the deflected jet and did not, apparently, contaminate the wake with heat. Recently Lomno et al (1994) have reported results which show a small amount of jet fluid entering a portion of the wake region.…”

Section: Tracking the Flmv Iwrticitymentioning

confidence: 99%

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Vortical structure in the wake of a transverse jet

1994

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Structural features resulting from the interaction of a turbulent jet issuing transversely into a uniform stream are described with the help of flow visualization and hot-wire anemometry. Jet-to-crossflow velocity ratios from 2 to 10 were investigated at crossflow Reynolds numbers from 3800 to 11400. In particular, the origin and formation of the vortices in the wake are described and shown to be fundamentally different from the well-known phenomenon of vortex shedding from solid bluff bodies. The flow around a transverse jet does not separate from the jet and does not shed vorticity into the wake. Instead, the wake vortices have their origins in the laminar boundary layer of the wall from which the jet issues. It is argued that the closed flow around the jet imposes an adverse pressure gradient on the wall, on the downstream lateral sides of the jet, provoking 'separation events' in the wall boundary layer on each side. These result in eruptions of boundary-layer fluid and formation of wake vortices that are convected downstream. The measured wake Strouhal frequencies, which depend on the jet-crossflow velocity ratio, match the measured frequencies of the separation events. The wake structure is most orderly and the corresponding wake Strouhal number (0.13) is most sharply defined for velocity ratios near the value 4. Measured wake profiles show deficits of both momentum and total pressure.

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Section: Tracking the Flmv Iwrticitymentioning

confidence: 99%

“…and (c) plan view at the base of a wall-mounted circular cylinder. Crossflow Reynolds number equals 3800 in each case. following: Keffer & Baines (1963), Pratte & Baines (1967), Kamotani & Greber (1972), and Fearn & Weston (1974).…”

Section: : Fricmentioning

confidence: 99%

Vortical structure in the wake of a transverse jet

1994

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“…However, the present data do indicate asymmetric structure and decreasing asymmetry with increasing Reynolds number in the flow-regime investigated. The general asymmetry of the transverse jet at downstream locations has been noted in experimental studies by Kamotani & Greber (1972) and Smith & Mungal (1998), among others. Smith and Mungal (1998) review the evidence for asymmetry in the transverse jet and conclude that it is quite common in experiments, although symmetry is often assumed in computational investigations.…”

Section: Space-time Visualizationmentioning

confidence: 96%

“…A number of early studies focused on classical measures of jet mixing such as scalar trajectories, centreline concentration decay, and mean scalar fields (e.g. Patrick 1967;Kamotani & Greber 1972). Broadwell & Breidenthal (1984) made an important contribution by modelling the transverse jet as an axial vortex pair that arises as a global consequence of the transverse lift force imparted by the jet to the crossflow.…”

Section: Introductionmentioning

confidence: 99%

Reynolds-number effects and anisotropy in transverse-jet mixing

Shan

Dimotakis

2006

J. Fluid Mech.

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Experiments are described which measured concentration fields in liquid-phase strong transverse jets over the Reynolds-number range 1.0 × 10 3 6 Re j 6 20 × 10 3 . Laserinduced-fluorescence measurements were made of the jet-fluid-concentration fields at a jet-to-freestream velocity ratio of V r = 10. The concentration-field data for far-field (x/d j = 50) slices of the jet show that turbulent mixing in the transverse jet is Reynoldsnumber dependent over the range investigated, with a scalar-field PDF that evolves with Reynolds number. A growing peak in the PDF, indicating enhanced spatial homogenization of the jet-fluid concentration field, is found with increasing Reynolds number. Comparisons between transverse jets and jets discharging into quiescent reservoirs show that the transverse jet is an efficient mixer in that it entrains more fluid than the ordinary jet, yet is able to effectively mix and homogenize the additional entrained fluid. Analysis of the structure of the scalar field using distributions of scalar increments shows evidence for well-mixed plateaux separated by sharp cliffs in the jet-fluid concentration field, as previously shown in other flows. Furthermore, the scalar field is found to be anisotropic, even at small length scales. Evidence for local anisotropy is seen in the scalar power spectra, scalar microscales, and PDFs of scalar increments in different directions. The scalar-field anisotropy is shown to be correlated to the vortex-induced large-scale strain field of the transverse jet. These experiments add to the existing evidence that the large and small scales of high-Schmidt-number turbulent mixing flows can be linked, with attendant consequences for the universality of small scales of the scalar field for Reynolds numbers up to at least Re = 20 × 10 4 .

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“…The interaction of the jets with the crossflow has been investigated in numerous experimental studies [1][2][3][4][5][6]. Crabb et al [2] present a comprehensive review of pre 1980 studies, most of which only deal with mean flow properties.…”

Section: Introductionmentioning

confidence: 99%

Multigrid acceleration and turbulence models for computations of 3D turbulent jets in crossflow

Demuren

1992

International Journal of Heat and Mass Transfer

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Experiments on a Turbulent Jet in a Cross Flow

Cited by 447 publications

References 2 publications

Vortical structure in the wake of a transverse jet

Vortical structure in the wake of a transverse jet

Reynolds-number effects and anisotropy in transverse-jet mixing

Multigrid acceleration and turbulence models for computations of 3D turbulent jets in crossflow

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