Three‐dimensional features of particle dispersion in a nominally plane mixing layer

1996 ◽  
Vol 8 (9) ◽  
pp. 2266-2268 ◽  
Author(s):  
B. Marcu ◽  
E. Meiburg
Keyword(s):  
Mixing Layer ◽  
Three Dimensional ◽  
Particle Dispersion ◽  
Plane Mixing Layer

Evolution of stream wise vortices and generation of small-scale motion in a plane mixing layer

1991 ◽  
Vol 231 ◽  
pp. 257-301 ◽  
Author(s):  
K. J. Nygaard ◽  
A. Glezer
Keyword(s):  
Surface Film ◽  
Mixing Layer ◽  
Excitation Frequency ◽  
Three Dimensional ◽  
Streamwise Velocity ◽  
Base Flow ◽  
Small Scale ◽  
Streamwise Vortices ◽  
Plane Mixing Layer ◽  
Scale Motion

The evolution of streamwise vortices in a plane mixing layer and their role in the generation of small-scale three-dimensional motion are studied in a closed-return water facility. Spanwise-periodic streamwise vortices are excited by a time-harmonic wavetrain with span wise-periodic amplitude variations synthesized by a mosaic of 32 surface film heaters flush-mounted on the flow partition. For a given excitation frequency, virtually any span wise wavelength synthesizable by the heating mosaic can be excited and can lead to the formation of streamwise vortices before the rollup of the primary vortices is completed. The onset of streamwise vortices is accompanied by significant distortion in the transverse distribution of the streamwise velocity component. The presence of inflexion points, absent in corresponding velocity distributions of the unforced flow, suggests the formation of locally unstable regions of large shear in which broadband perturbations already present in the base flow undergo rapid amplification, followed by breakdown to small-scale motion. Furthermore, as a result of spanwise-non-uniform excitation the cores of the primary vortices are significantly altered. The three-dimensional features of the streamwise vortices and their interaction with the base flow are inferred from surfaces of r.m.s. velocity fluctuations and an approximation to cross-stream vorticity using three-dimensional single component velocity data. The striking enhancement of small-scale motion and the spatial modification of its distribution, both induced by the streamwise vortices, can be related to the onset of the mixing transition.

Research on particle dispersion in a plane mixing layer with coherent structures

2003 ◽  
Vol 19 (6) ◽  
pp. 535-542 ◽  
Author(s):  
Lin Jonahing ◽  
Lin Jiang ◽  
Shao Xueming ◽  
Shi Xing
Keyword(s):  
Coherent Structures ◽  
Mixing Layer ◽  
Particle Dispersion ◽  
Plane Mixing Layer

A perspective view of the plane mixing layer

1985 ◽  
Vol 152 ◽  
pp. 125-143 ◽  
Author(s):  
Javier Jimenez ◽  
Marta Cogollos ◽  
Luis P. Bernal
Keyword(s):  
Computer Graphic ◽  
Mixing Layer ◽  
Motion Pictures ◽  
Three Dimensional ◽  
Quantitative Information ◽  
Laser Fluorescence ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Perspective View ◽  
Plane Mixing Layer

A three-dimensional model of the plane mixing layer is constructed by applying digital image processing to laser fluorescence motion pictures of the layer, and displayed using computer graphic techniques. A system of streamwise counterrotating vortices is shown to exist on top of the classical spanwise eddies, and its influence in mixing is discussed briefly. Some quantitative information on their strength is also given.

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