Positively buoyant jets: Semiturbulent to fully turbulent regimes

2021 ◽  
Vol 6 (5) ◽  
Author(s):  
H. Hassanzadeh ◽  
A. Eslami ◽  
S. M. Taghavi
Keyword(s):  
Buoyant Jets

Numerical Modeling of Vertical Buoyant Jets discharged from multiport diffusers

2016 ◽  
Author(s):  
Behnaz Ghodoosipour ◽  
◽  
ABDOLMAJID MOHAMMADIAN ◽  
Ioan Nistor
Keyword(s):  
Numerical Modeling ◽  
Buoyant Jets

Dynamic interaction of multiple buoyant jets

2012 ◽  
Vol 708 ◽  
pp. 539-575 ◽  
Author(s):  
Adrian C. H. Lai ◽  
Joseph H. W. Lee
Keyword(s):  
Stokes Equations ◽  
Dynamic Pressure ◽  
Unit Length ◽  
Iterative Solution ◽  
Scalar Fields ◽  
Passive Scalar ◽  
Dynamic Interaction ◽  
Ambient Conditions ◽  
Buoyant Jet ◽  
Buoyant Jets

AbstractAn array of closely spaced round buoyant jets interact dynamically due to the pressure field induced by jet entrainment. Mutual jet attraction can result in a significant change in jet trajectories. Jet merging also leads to overlapping of the passive scalar fields associated with the individual jets, resulting in mixing characteristics that are drastically different from those of an independent free jet. A general semi-analytical model for the dynamic interaction of multiple buoyant jets in stagnant ambient conditions is proposed. The external irrotational flow field induced by the buoyant jets is computed by a distribution of point sinks with strength equal to the entrainment per unit length along the unknown jet trajectories and accounting for boundary effects. The buoyant jet trajectories are then determined by an iterative solution of an integral buoyant jet model by tracking the changes in the external entrainment flow and dynamic pressure fields. The velocity and concentration fields of the jet group are obtained by momentum or kinetic energy superposition for merged jets and plumes, respectively. The modelling approach is supported by numerical solution of the Reynolds-averaged Navier–Stokes equations. The model shows that jet merging and mixing can be significantly affected by jet interactions. Model predictions of the multiple jet trajectories, merging height, as well as the centreline velocity and concentration of the buoyant jet group are in good agreement with experimental data for: (i) a clustered momentum jet group; (ii) a turbulent plume pair; and (iii) a rosette buoyant jet group. Dynamic interactions between a jet group are shown to decrease with the addition of an ambient cross-flow.

On Prediction and Unified Correlation for Decay of Vertical Buoyant Jets

1979 ◽  
Vol 101 (3) ◽  
pp. 532-537 ◽  
Author(s):  
C. J. Chen ◽  
C. H. Chen
Keyword(s):  
Kinetic Energy ◽  
Scaling Law ◽  
Flow Characteristics ◽  
Heat Fluxes ◽  
Buoyant Jets ◽  
Numerical Result ◽  
Plume Region ◽  
Unified Scaling Law ◽  
Rate Of Dissipation ◽  
Decay Behavior

A differential turbulence model is used to predict the decay behavior of turbulent buoyant jets in a uniform environment at rest. The turbulent stresses and heat fluxes are modeled by the algebraic expressions while the differential transport equations are solved for the kinetic energy of turbulence, k, the rate of dissipation of turbulence kinetic energy, ε, and the fluctuating temperature T′2. The numerical result correlated with a unified scaling law was shown to fall into a single curve for the flows beyond the zone of flow establishment. The flow characteristics are then classified into a non-buoyant region, an intermediate region and a plume region. The predicted results show that the buoyant jets is accelerated in the zone of flow establishment. Equations for decay of velocity, density, and turbulent quantities are given from the non-buoyant region to the plume region for both plane and round buoyant jets.

Modeling and experimental studies on air buoyant jets for application to small containments

2017 ◽  
Vol 109 ◽  
pp. 212-219
Author(s):  
Tengfei Ma ◽  
Fenglei Niu ◽  
Weiqian Zhuo ◽  
Yeyun Wang ◽  
Taskeen Warraich ◽  
...  
Keyword(s):  
Experimental Studies ◽  
Buoyant Jets

Discussion of “Two-Dimensional Buoyant Jets in Stratified Fluid”

1980 ◽  
Vol 106 (10) ◽  
pp. 1720-1720
Author(s):  
J.-C. Chen ◽  
E. J. List ◽  
P. N. Papanicolaou
Keyword(s):  
Stratified Fluid ◽  
Two Dimensional ◽  
Buoyant Jets

Spread of Buoyant Jets at the Free Surface - II

1969 ◽  
Vol 95 (5) ◽  
pp. 1771-1773
Author(s):  
James J. Sharp
Keyword(s):  
Free Surface ◽  
Buoyant Jets

scholarly journals Vertical Round Buoyant Jets and Fountains in a Linearly, Density-Stratified Fluid

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 232
Author(s):  
Panos N. Papanicolaou ◽  
George C. Stamoulis
Keyword(s):  
Steady State ◽  
Laboratory Experiments ◽  
Coefficient Function ◽  
Buoyant Jets ◽  
Asymptotic Values ◽  
Entrainment Coefficient ◽  
Source Level ◽  
The Mean ◽  
Negatively Buoyant ◽  
Negatively Buoyant Jets

Turbulent round buoyant jets and fountains issuing vertically into a linearly density-stratified calm ambient have been investigated in a series of laboratory experiments. The terminal (steady-state) height of rise and the mean elevation of subsequent horizontal spreading have been measured in positively buoyant jets (at source level), including pure momentum jets and plumes, as well in momentum-driven negatively buoyant jets (fountains). The results from experiments confirmed the asymptotic analysis that was based on dimensional arguments. The normalized terminal height and spreading elevation with respect to the elevation of injection of momentum-driven (positively) buoyant jets and fountains attained the same asymptotic values. The numerical results from the solution of entrainment equations, using an improved entrainment coefficient function, confirmed the results related to buoyancy dominant flows (plumes), while their predictions in momentum-driven flows were quite low if compared to measurements.

scholarly journals Flow behaviour of negatively buoyant jets in immiscible ambient fluid

2011 ◽  
Vol 52 (1) ◽  
pp. 261-271 ◽  
Author(s):  
A. Geyer ◽  
J. C. Phillips ◽  
M. Mier-Torrecilla ◽  
S. R. Idelsohn ◽  
E. Oñate
Keyword(s):  
Flow Behaviour ◽  
Ambient Fluid ◽  
Buoyant Jets ◽  
Negatively Buoyant ◽  
Negatively Buoyant Jets
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