Dynamic interaction of multiple buoyant jets

Lai, Adrian C. H.; Lee, Joseph Hun Wei

doi:10.1017/jfm.2012.332

Cited by 50 publications

(31 citation statements)

References 36 publications

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“…This predicted a merging height for two plumes approximately twice the distance observed by Kaye & Linden (2004). Circular arrays of multiple buoyant jets were also modelled by Lai & Lee (2012) using a semi-analytical approach. Like the other models described, this did not allow for the distortion of individual plume cross-sections, but did represent the field external to the jets as an irrotational flow based on a distribution of point sinks.…”

Section: Introductionmentioning

confidence: 99%

Merging of two or more plumes arranged around a circle

Rooney

2016

J. Fluid Mech.

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A model is presented of merging turbulent plumes from sources evenly spaced around a horizontal circle in a quiescent, unstratified background. This follows the previously developed method of (i) identifying the boundaries of interacting plumes with velocity-potential contours of line sinks and (ii) closing the generalised plume equations with an entrainment assumption based on the integrated flux across the plume boundaries. It includes the simplest case of two merging plumes, as well as being applicable to plume flows in restricted corner configurations. The model is shown to display the expected limiting behaviour for the source plumes and the merged plume. Consideration of the plume fluxes in the merging region leads to a revision of the entrainment assumption. The resulting revised model compares satisfactorily with previous estimates of volume flux in two merging plumes.

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Section: Introductionmentioning

confidence: 99%

Merging of two or more plumes arranged around a circle

Rooney

2016

J. Fluid Mech.

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“…A model was developed to calculate the rate of change of the volume flux after the two plumes have touched and before they have merged. This region was investigated for multiple turbulent buoyant jets using a superposition approach by Yannopoulos & Noutsopoulos (2006a,b) and Lai & Lee (2012), but its effects appear to have been ignored since it was observed to be smaller in vertical extent than the region over which the two plumes draw together (Baines 1983, KL04). The present model predicts that the total volume flux in the two touching plumes increases linearly between z T z z M .…”

Section: Discussionmentioning

confidence: 99%

“…Coastal cities often discharge their partially treated waste waters at the bottom of the ocean via an outfall. Ocean outfall design is governed by the dynamics regulating the interaction of multiple buoyant jets (Lai & Lee 2012;Lee 2012) and their ability to dilute the waste waters. Finally, the dynamics of buoyant vertical plumes has recently been shown to have an important role in the melting of some vertical glacier faces (Jenkins 2011;Xu et al 2012;Sciascia et al 2013).…”

Section: Introductionmentioning

confidence: 99%

“…One of the first studies investigating the interaction between multiple jets focused on the development of clouds (Baines & Keffer 1975), which was followed by further work focusing on buoyant plumes close to ideal, i.e. with small initial volume and momentum fluxes, by Baines (1983) and Kaye & Linden (2004), and work focusing on buoyant jets with significant momentum fluxes (Yannopoulos & Noutsopoulos 2006a,b;Lai & Lee 2012). In particular, Kaye & Linden (2004) made the first detailed study on coalescing plume pairs focused on the condition for merging.…”

Section: Introductionmentioning

confidence: 99%

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Entrainment in two coalescing axisymmetric turbulent plumes

Cenedese

Linden

2014

J. Fluid Mech.

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A model of the total volume flux and entrainment occurring in two coalescing axisymmetric turbulent plumes is developed and compared with laboratory experiments. The dynamical evolution of the two plumes is divided into three regions. In region 1, where the plumes are separate, the entrainment in each plume is unaffected by the other plume, although the two plumes are drawn together due to the entrainment of ambient fluid between them. In region 2 the two plumes touch each other but are not yet merged. In this region the total entrainment is a function of both the dynamics of the touching plumes and the reduced surface area through which entrainment occurs. In region 3 the two plumes are merged and the entrainment is equivalent to that in a single plume. We find that the total volume flux after the two plumes touch and before they merge increases linearly with distance from the sources, and can be expressed as a function of the known total volume fluxes at the touching and merging heights. Finally, we define an 'effective' entrainment constant, α eff , as the value of α needed to obtain the same total volume flux in two independent plumes as that occurring in two coalescing plumes. The definition of α eff allows us to find a single expression for the development of the total volume flux in the three different dynamical regions. This single expression will simplify the representation of coalescing plumes in more complex models, such as in large-scale geophysical convection, in which plume dynamics are not resolved. Experiments show that the model provides an accurate measure of the total volume flux in the two coalescing plumes as they evolve through the three regions.

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“…Regarding the spread of thermal effluents in the steady flow, there have been various theoretical analysis, numerical simulation, and experimental measurements, with focus on velocity distribution in axial and radial directions (EI-Amin et al, 2010), gradient of hydrothermal field (Jiang et al, 2003;Tang et al, 2008), fluxes of mass, momentum, and buoyancy (EI-Amin et al, 2010), bifurcation of jet (Wang et al, 2012), coherent vortex structures (Yuan et al, 1999), trajectory and cling length (Gildeh et al, 2014), entrainment (McGuirk andRodi, 1979), and obstructed buoyant jets (Huai and Fang, 2006;Huai et al, 2006). Similar investigations were also been performed for contaminant discharge (Lee and Cheung, 1986;Jirka and Akar, 1991;Yoda et al, 1994;Méndez-Díaz and Jirka, 1996;Roberts et al, 1997Roberts et al, , 2001Arakeri et al, 2000;Diez et al, 2005;Papanicolaou et al, 2008;Lai and Lee, 2012;Lee, 2012;Abessi and Roberts, 2014).…”

Section: Introductionmentioning

confidence: 99%