Buoyant jets with three-dimensional trajectories

Kikkert, Gustaaf Adriaan; Davidson, M. J.; Nokes, Roger

doi:10.1080/00221681003726270

Cited by 28 publications

(69 citation statements)

References 9 publications

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“…Thus, the entrainment and the distribution of buoyancy within the predominantly horizontal flow is expected to be skewed (i.e. asymmetric about the centreline) and laterally constrained by the buoyancy force -an expectation qualitatively supported by the data of [37]. The lateral constraint would result in a reduced spread (variance) in the distribution of the buoyancy and, hence, we propose to account for these near-field effects with a reduction in λ.…”

Section: E Forming Free Jets and Clinging Jetsmentioning

confidence: 63%

“…However, the good agreement between the predictions of the model and our measurements indicates that either the variations due to differences in the angle of the plane of measurement are not significant or the parameterisation somehow accounts for these variations. Figure 5 shows the variation in volume flux for free jets from Kikkert [21] Michas \& Papanicolaou [22] Yannopoulos \& Bloutsos [16] Z/(r 0 ther from the source than we were able to gather data in our experiments. This agreement (for z 14) between model predictions and the data inferred from centreline dilutions published in other studies suggests that our parameterisation exhibits no significant bias due to being determined by our measurements of the fluxes across horizontal planes (for z 6).…”

Section: E Forming Free Jets and Clinging Jetsmentioning

confidence: 86%

“…Research has gone some way to providing insights for answering such questions but developing an understanding of the full problem is non-trivial. Even for the simplified case of a horizontal buoyant free jet in a quiescent uniform ambient, examination of the existing data for the location of the jet centreline [17][18][19][20][21][22] and jet dilution [20][21][22] reveals a relatively wide spread of results. Alongside enhancing our understanding of clinging jets, an objective of this study is to provide an extensive dataset for free jets in order to enable comparisons with these existing datasets.…”

Section: Background and Contextmentioning

confidence: 99%

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From free jets to clinging wall jets: The influence of a horizontal boundary on a horizontally forced buoyant jet

Burridge

Hunt

2017

Phys. Rev. Fluids

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We investigate the incompressible turbulent jet formed when buoyant fluid is steadily ejected horizontally from a circular source into an otherwise quiescent uniform environment. As our primary focus, we introduce a horizontal boundary beneath the source. For sufficiently small separations, the jet attaches and clings to the boundary, herein the 'clinging jet', before, further downstream, the jet is pulled away from the boundary by the buoyancy force. For larger sourceboundary separations, the buoyant jet is free to rise under the action of the buoyancy force, herein the 'free jet'. Based on measurements of saline jets in freshwater surroundings we deduce the conditions required for a jet to cling. We present a data set that spans a broad range of source conditions for the variation in volume flux (indicative of entrainment), jet perimeter and jet centreline for both 'clinging' and 'free' jets. For source Froude numbers Fr 0 ≥ 12 the data collapses when scaled, displaying universal behaviours for both clinging and free jets. Our results for the variation in the volume flux across horizontal planes, πQ jet , show that within a few jet-lengths of the source, πQ jet for the clinging jet exceeds that of a free jet with identical source conditions. However, when examined in a coordinate following the jet centreline πQ jet for free jets is greater.Finally, we propose a new parameterisation for an existing integral model which agrees well with our experimental data as well as with data from other studies. Our findings offer the potential to tailor the dilution of horizontal buoyant jets by altering the distance at which they are released from a boundary.

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Section: E Forming Free Jets and Clinging Jetsmentioning

confidence: 63%

Section: E Forming Free Jets and Clinging Jetsmentioning

confidence: 86%

Section: Background and Contextmentioning

confidence: 99%

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From free jets to clinging wall jets: The influence of a horizontal boundary on a horizontally forced buoyant jet

Burridge

Hunt

2017

Phys. Rev. Fluids

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“…This relationship can be expressed as a simple equation for low dye concentrations [3]. With this relationship dye concentration can then act as a proxy for fluid density provided strict control of temperature in the darkened laboratory is maintained [12]. Shutter-speed, aperture, and white balance of the digital camera were preset to optimize the intensity range; errors associated with temperature and light fluctuations after calibration were less than 5%.…”

Section: Methodsmentioning

confidence: 99%

The generation of internal waves by tidal flow over continental shelf/slope topography

2008

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Experiments were performed to investigate the generation of internal waves induced by a barotropic tidal flow over continental shelf/slope topography in a two-layer stratified fluid. The interaction of the barotropic tide with the continental slope resulted in the formation of both linear and nonlinear waveforms, ranging from a linear wave of depression to a highly nonlinear internal bolus. The type of wave response was strongly dependent on the tidal forcing intensity and the position of the density interface relative to the shelf depth. Based on the values of the internal Froude number and the layer depth ratio, we delineate four distinct generation regimes, each with a distinct wave response.

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“…Cipollina et al (2005) [2] studied angles of 30°, 45° and 60° with different Froude number, focusing on the maximum height, distance from the source and dilution of the impact point. Kikkert et al (2007 [22], 2010 [23]) studied different horizontal and vertical inclination of the release, and of the ambient receptor, measuring dilution and trajectories. Papakostantis et al (2011a [24], 2011b [25]) focusing on inclination between 45° to 90°, at different Froude number, measured among others, the turbulent concentration fluctuation (C rms ) and the geometrical characteristics of the jet.…”

Section: Introductionmentioning

confidence: 99%

Experimental Studies for the characterization of the mixing processes in negative buoyant jets

Besalduch

Badas

Ferrari

et al. 2013

EPJ Web of Conferences

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Abstract.A negatively buoyant jet (NBJ) corresponds to the physical phenomenon that develops when a fluid is discharged upwards into a lighter environment or downwards into a heavier receptor fluid. In a NBJ the flow is initially driven mostly by the momentum, so it basically behaves as a simple jet released with the same angle, while far from the outlet the buoyancy prevails, bending the jet axis down and making it similar to a plume. The coexistence in the same phenomenon of both the characteristics of simple jets and plumes makes the NBJs a phenomenon still not entirely explained but, considering also the numerous practical applications, very interesting to study. Here some of the experimental results are presented. The laboratory experiment were obtained on a model simulating a typical sea discharge of brine from desalination plants: a pipe laid down on the sea bottom, with orifices on its lateral wall, releasing brine (heavier than the sea water) with a certain angle to the horizontal, in order to increase the jet path before sinking to the seafloor. A non-intrusive image analysis technique, namely Feature Tracking Velocimetry, is applied to measure velocity fields, with the aim at understanding the influence of some non-dimensional parameters driving the phenomenon (e.g. Reynolds number, release angle) on the structure of the NBJ and of the turbulence.

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Buoyant jets with three-dimensional trajectories

Cited by 28 publications

References 9 publications

From free jets to clinging wall jets: The influence of a horizontal boundary on a horizontally forced buoyant jet

From free jets to clinging wall jets: The influence of a horizontal boundary on a horizontally forced buoyant jet

The generation of internal waves by tidal flow over continental shelf/slope topography

Experimental Studies for the characterization of the mixing processes in negative buoyant jets

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