Multiple vortex ring model of the DFW microburst

A phenomenological study of vortex ring-like structures in gasoline fuel sprays is presented for two types of production fuel injectors: a low-pressure, port fuel injector (PFI) and a high-pressure atomizer that injects fuel directly into an engine combustion chamber (G-DI). High-speed photography and phase Doppler anemometry (PDA) were used to study the fuel sprays. In general, each spray was seen to comprise three distinct periods: an initial, unsteady phase; a quasi-steady injection phase; and an exponential trailing phase. For both injectors, vortex ring-like structures could be clearly traced in the tail of the sprays. The location of the region of maximal vorticity of the droplet and gas mixture was used to calculate the temporal evolution of the radial and axial components of the translational velocity of the vortex ring-like structures. The radial components of this velocity remained close to zero in both cases. The experimental results were used to evaluate the robustness of previously developed models of laminar and turbulent vortex rings. The normalized time, , and normalized axial velocity, , were introduced, where tinit is the time of initial observation of vortex ring-like structures. The time dependence of on was approximated as and for the PFI and G-DI sprays respectively. The G-DI spray compared favourably with the analytical vortex ring model, predicting , in the limit of long times, where α = 3/2 in the laminar case and α = 3/4 when the effects of turbulence are taken into account. The results for the PFI spray do not seem to be compatible with the predictions of the available theoretical models.

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A coaxial vortex ring model for vortex breakdown

Physica D Nonlinear Phenomena ◽

10.1016/j.physd.2008.05.012 ◽

2008 ◽

Vol 237 (22) ◽

pp. 2817-2844 ◽

Cited By ~ 5

Author(s):

Denis Blackmore ◽

Morten Brøns ◽

Arnaud Goullet

Keyword(s):

Vortex Ring ◽

Vortex Breakdown ◽

Ring Model

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A multiple-vortex-ring model of the DFW microburst

10.2514/6.1988-685 ◽

1988 ◽

Cited By ~ 3

Author(s):

THOMAS SCHULTZ

Keyword(s):

Vortex Ring ◽

Ring Model

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Vortex-ring model of Bose condensation

Physica ◽

10.1016/0031-8914(73)90348-0 ◽

1973 ◽

Vol 65 (2) ◽

pp. 321-336 ◽

Cited By ~ 23

Author(s):

F.W. Wiegel

Keyword(s):

Vortex Ring ◽

Bose Condensation ◽

Ring Model

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Vortex-ring model of the superfluidλtransition

Physical Review Letters ◽

10.1103/physrevlett.59.1926 ◽

1987 ◽

Vol 59 (17) ◽

pp. 1926-1929 ◽

Cited By ~ 106

Author(s):

Gary A. Williams

Keyword(s):

Vortex Ring ◽

Ring Model

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CHARACTERISTICS OF THE JET IMPACT DURING THE INTERACTION BETWEEN A BUBBLE AND A WALL

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194516601575 ◽

2016 ◽

Vol 42 ◽

pp. 1660157

Author(s):

SHUAI LI ◽

SHI-PING WANG ◽

A-MAN ZHANG

Keyword(s):

Vortex Ring ◽

Rigid Wall ◽

Boundary Integral ◽

Boundary Integral Method ◽

Maximum Pressure ◽

Inviscid Incompressible Fluid ◽

Ring Model ◽

Toroidal Bubble ◽

Jet Impact ◽

Bubble Splitting

The dynamics of a toroidal bubble splitting near a rigid wall in an inviscid incompressible fluid is studied in this paper. The boundary integral method is adopted to simulate the bubble motion. After the jet impact, the vortex ring model is used to handle the discontinued potential of the toroidal bubble. When the toroidal bubble is splitting, topology changes are made tear the bubble apart. Then, the vortex ring model is extended to multiple vortex rings to simulate the interaction between two toroidal bubbles. A typical case is discussed in this study. Besides, the velocity fields and pressure contours surrounding the bubble are used to illustrate the numerical results. An annular high pressure region is generated at the splitting location, and the maximum pressure may be much higher than the jet impact. More splits may happen after the first split.

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