Passive Scalar Transport in a Turbulent Mixing Layer

Li, Ning; Balaras, Elias; Wallace, J. M.

doi:10.1007/s10494-010-9249-4

Cited by 26 publications

(8 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The distributions of kinetic energy fluctuations are in accordance with that of the large vortex structures in Figure 4a. The larger value of the kinetic energy fluctuations always exists at the location where the braid, the region connecting the rollers, and the rollers meet but the vortex cores which is in good agreement with Li et al (2009). Different from $u'^{2} /(u_{{\rm h}} - u_{{\rm l}} )^{2} $ and $v'^{2} /(u_{{\rm h}} - u_{{\rm l}} )^{2} $ , $u'v'/(u_{{\rm h}} - u_{{\rm l}} )^{2} $ appears both negative and positive values around the same vortex structure.…”

Section: Resultssupporting

confidence: 90%

Investigation of turbulent mixing layer flow in a vertical water channel by particle image velocimetry (PIV)

Guo¹,

Chen²,

Guo³

et al. 2010

Can J Chem Eng

View full text Add to dashboard Cite

Turbulent mixing layer flow in a vertical water channel was experimentally investigated by particle image velocimetry (PIV). The mixing layer is produced by a specially designed insert plate placed in the channel with a low-and high-speed side velocity ratio of 0.25. The Reynolds number based on the velocity difference of two streams and the spanwise vorticity thickness at the place where the mixing layer start merging ranges from 2184 to 14 672. The results show that there are large coherent vortex structures near the centreline of the mixing layer. Both instantaneous kinetic energy and spanwise vorticity always concentrate at the location where the coherent structures connect or meet each other. The normalised dimensionless Reynolds stresses and average spanwise vorticity show self-similar, respectively, under different Reynolds numbers at the same cross-section in the down streamwise direction. Every component of Reynolds stresses increases but the vorticity decreases with the downstream distance. For all Reynolds number, the peak values of mean vorticity in the streamwise direction appear the same decay speed. The splitter plane wake causes a negative peak of the mean vorticity where the mixing layer merges. The negative peak values of vorticity increase with the Reynolds number. The dimensionless negative peak values decrease exponentially with Reynolds number and reach a constant when the Reynolds number is large enough.Le débit de couche de mélange turbulent dans une conduite d'eau verticale aété analysé de façon expérimentale par vélocimétrie par images de particules (PIV). La couche de mélange est produiteà l'aide d'une plaque d'insertion de conception particulière placée dans le conduit avec un rapport de vitesse latérale basse etélevée de 0,25. Le nombre de Reynolds fondé sur la différence de vitesse de deux courants et l'épaisseur du tourbillon dans le sens de l'envergureà l'endroit où la couche de mélange commenceà fusionner se situe entre 2,184∼14,672. Les résultats indiquent qu'il existe de grandes nappes de tourbillons cohérentes près de la ligne centrale de la couche de mélange.À la fois l'énergie cinétique instantanée et le tourbillon dans le sens de l'envergure se concentrent toujoursà l'endroit où les nappes cohérentes se rencontrent. Les tensions de Reynolds normalisées adimensionnelles et le tourbillon dans le sens de l'envergure moyen démontrent qu'ils sont autosimilaires respectivement sous différents nombres de Reynoldsà la même section transversale en aval. Chaqueélément des tensions de Reynolds s'accroît, mais le tourbillon diminue avec la distance en aval. Pour tout nombre de Reynolds, les valeurs de crête du tourbillon moyen dans la direction du flux semblentêtre de la même vitesse de désintégration. Le sillage plan de séparation cause une crête négative de tourbillon moyen lorsque la couche de mélange est fusionnée. Les valeurs de crête négatives du tourbillon augmentent avec le nombre de Reynolds. Les valeurs de crête négatives adimensionnelles diminuent de façon exponentielle avec ...

show abstract

Section: Resultssupporting

confidence: 90%

Investigation of turbulent mixing layer flow in a vertical water channel by particle image velocimetry (PIV)

Guo¹,

Chen²,

Guo³

et al. 2010

Can J Chem Eng

View full text Add to dashboard Cite

show abstract

“…Zhou & Pereira (2000) and Wang & Milane (2006) have performed two-dimensional spatial simulations which successfully replicated the entrainment, mixing and chemical reaction in the low-Reynolds-number isothermal reacting mixing layer studied experimentally by Masutani & Bowman (1986) whilst two-dimensional simulations of fully turbulent laboratory mixing layers have been attempted by Jaberi et al (1999) and Yang et al (2004aYang et al ( , 2004b. Three-dimensional simulations of fully turbulent laboratory mixing layers have been reported by Li, Balaras & Piomelli (2000), Tenaud et al (2005), Li, Balaras & Wallace (2010) and Biancofiore (2014). In most of these studies the principal motivation for making comparisons with experimental data has been to test aspects of the LES methodology and in no case was any very detailed study made of the evolution of the coherent structures.…”

Section: Introductionmentioning

confidence: 93%

Organised large structure in the post-transition mixing layer. Part 2. Large-eddy simulation

McMullan¹,

Gao²,

Coats³

2014

J. Fluid Mech.

View full text Add to dashboard Cite

Three-dimensional large-eddy simulations of two-stream mixing layers developing spatially from laminar boundary layers are presented, replicating wind-tunnel experiments carried out in Part 1 of this study. These simulations have been continued through the mixing transition and into the fully turbulent self-similar flow beyond. In agreement with the experiments, the simulations show that the familiar mechanism of growth by vortex amalgamation is replaced at the mixing transition by a previously unrecognised mechanism in which the spanwise-coherent large structures individually undergo continuous linear growth. In the post-transition flow it is this continuous linear growth of the individual structures that produces the self-similar growth of the mixing-layer thickness, the large-structure interactions occurring as a consequence of the growth, not its cause. New information is also presented on the topography of the organised post-transition flow and on its cyclical evolution through the lifetimes of the individual large structures. The dynamic and kinematic implications of these findings are discussed and shown to define quantitatively the growth rate of the homogeneous post-transition mixing layer in its organised state. _______________________________________________________________

show abstract

“…In most studies of turbulent mixing layers [5,14,31], the results are non-dimensionalised or normalised, typically using an average velocity and the initial roller diameter or splitter plate boundary layer thickness. This is because in the conditions tested by others, there has been a constant stream of regular rollers.…”

Section: Resultsmentioning

confidence: 99%

Vertical mixing layer development

Robinson

Richon

Bryden

et al. 2014

European Journal of Mechanics - B/Fluids

View full text Add to dashboard Cite

A new generation of current and wave testing tanks is required to simulate more realistic sea conditions at larger scales. One means of producing a current is by using groups of impellers arranged around the perimeter of a circular tank. Each propeller produces a single flow velocity which may be different to its neighbours. These differences can lead to a stepped or curved plan view velocity profile in the test section of the tank where a plug profile is required. It is important to understand what the maximum allowable velocity difference between each impeller can be before the required plug profile in the test section is compromised. The situation where two individual fluid streams combine, leading to a turbulent mixing layer, is found in many applications and is therefore of great interest in wider fluid dynamics. In the experimental work presented a setup is described which combines two water flows at different velocities to create a vertical shear. The evolution of the combined flow is studied using Particle Image Velocimetry (PIV). When analysed, these results lead to an understanding of various aspects of mixing layer flow recovery and how the bulk flow rates and velocity ratio affected them.

show abstract

Passive Scalar Transport in a Turbulent Mixing Layer

Cited by 26 publications

References 32 publications

Investigation of turbulent mixing layer flow in a vertical water channel by particle image velocimetry (PIV)

Investigation of turbulent mixing layer flow in a vertical water channel by particle image velocimetry (PIV)

Organised large structure in the post-transition mixing layer. Part 2. Large-eddy simulation

Vertical mixing layer development

Contact Info

Product

Resources

About