Vortex Pair

Winant, D., and F. K. Browand. 1974. Vortex pairing, the mechanism of turbulent mixing-layer growth at moderate Reynolds number. J. Fluid Mechanics 63 237-55. 

Figure 12. Lagrangian path lines at various stages of a Rayleigh-Taylor collapse for the case of two inviscid, incompressible fluids having a density ratio of 2 1. A free surface is present above the dense fluid and the interface between the fluids is indicated for each stage. The simulation shows how later evolution of the fluid flow is dominated by the strength and dynamics of the vortex pair created during the...

The imposed Cartesian velocity components Uoo and v o are plotted in Fig. 2.31 for the indicated parameters, over a single vortex pair spacing given by a = IOOttJ The input disturbances are shown for a single period with Y = 18(5 and these are calculated at y = 16(5. ... 

At steady state, about 21 counter rotating vortex pairs were observed and the dimension of the each counter rotating pair was almost twice the gap of the armular space. It was also observed that... 

Of significant interest are the strong counter-rotating vortices observed in lateral cross-sections. In the region of the sweep, these vortices rotate such that the central area between them is one of downward flow, as shown in Figure 4.11. Following the vortex pair in the streamwise direction, the centres of rotation are observed to be tilted upwards. 

Compared with model one, because of lack of shunt plate, movement of vortex pairs of model two is very unsteady, which will influence the continuity and stability of high-speed airflow, through velocity is swifter because of the change of filter layout, the distance between the first filter and entrance extended segment become small, the vortex make the first filter nearly useless, which cause the velocity of air flow reduce about 1/3. 

Anemometric investigations of Bakewell and Lumley (11) and Blackwelder and Eckelmann (20) as well as visual investigations carried out recently by Smith and Schwartz (10) give evidence for the existence of counter-rotating stream-wise vortex pairs. It is generally assumed that the vortex pairs are responsible for the lift up of fluid from the wall. Fig. 3 shows the vortex model proposed by Blackwelder and Eckelmann. The sense of rotation of the two vortices is such that they pump low speed fluid away from the wall and simultaneously... 

In Figure 2.3, the flow regimes and pressure loss in T-joints are displayed for divergent flow. The side view clearly indicates the double vortex in the curved flow. In 90° bends, a secondary vortex pair is formed at higher Reynolds numbers Re >500). The T-joint with a wedge has a triangular-like wall shape at the stagnation point. 

The product distribution along the vortex pair in both images also depicts the 3D flow structure for higher Re in T-shaped micromixers. 

In all cases a single vortex pair, occupying the full emnulus length, is found to be present at vanishingly snail Taylor nunber (Fig. 2). As T increases, the nunber of vortex pairs is increased by the formation of new vortex pairs at the centre of the annulus (Figs 3,4). 

Karagozian, A.R. Manda, B.V.S. (1986), "Flame Structure and Fuel Consumption in the Field of a Vortex Pair." Combustion Science and Technology. V. 49, pp 185-200. 

Karagozian, A.R., Siiganuma, Y, Strom, B.D. (1987), "Experimental Studies in Vortex Pair Motion Coincident with a Liquid Reaction" Submitted to Physics of Fluids. 

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