Model of fourth-order cumulants for description of turbulent transport by large-scale vortex structures

The dispersion of particles in a plane mixing layer between two air streams is investigated using experimental and numerical techniques. The results show that large-scale spanwise vortices strongly influence the particle dispersion process. Particles with aerodynamic response times on the order of the large scale vortex time scales are found to concentrate near the outer edges of the vortex structures. Time average velocity measurements also demonstrate that these particles tend to move away from the center of the mixing layer. Substantial changes in the lateral particle dispersion are producible by controlled forcing of the vortex structures. Comparisons between the experimental particle dispersion patterns and numerical simulations show striking similarities. A two-part model involving stretching and folding is suggested as a particle dispersion mechanism.

Download Full-text

Modulations on turbulent characteristics by dispersed particles in gas–solid jets

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2005.1517 ◽

2005 ◽

Vol 461 (2062) ◽

pp. 3279-3295 ◽

Cited By ~ 7

Author(s):

Kun Luo ◽

Jianren Fan ◽

Kefa Cen

Keyword(s):

Large Scale ◽

Stokes Number ◽

Vortex Structures ◽

Half Width ◽

Mean Velocity ◽

Turbulent Characteristics ◽

Velocity Decay ◽

Large Scale Vortex ◽

High Reynolds ◽

The One

A direct numerical simulation technique combined with a two-way coupling method was developed to study a gas–solid turbulent jet with a moderately high Reynolds number. The flow was weakly compressible and spatially developing. A high-resolution solver was performed for the gas phase flow-field and the Lagrangian method was used to trace particles. The modulations on flow structures and other turbulent characteristics by particles at different Stokes numbers were investigated. It is found that the particles at Stokes numbers of 0.01 and 50 can advance the development of the large-scale vortex structures and make the turbulence intensity profiles wider and lower, but the particles at a Stokes number of 1 delay the evolution of the large-scale vortex structures and decrease the turbulence intensities. The jet velocity half-width and the decay of the streamwise mean velocity in the jet centreline are reduced by all particles, in which particles at a Stokes number of 0.01 result in a larger reduction of the velocity half-width and particles at a Stokes number of 1 lead to a larger reduction of the streamwise mean velocity decay. All particles decrease the vorticity thickness, but increase the fluid momentum thickness. In addition, the two-way coupled particle distribution is more uniform than that of the one-way coupled case.

Download Full-text

On large-scale vortex structures and flame front corrugations in swirling jets with combustion

10.1063/5.0001025 ◽

2020 ◽

Author(s):

Dmitriy Markovich ◽

Vladimir Dulin

Keyword(s):

Flame Front ◽

Large Scale ◽

Vortex Structures ◽

Swirling Jets ◽

Large Scale Vortex

Download Full-text

Visualization of the large-scale vortex structures in excited turbulent jets

Journal of Visualization ◽

10.1007/bf03181471 ◽

2003 ◽

Vol 6 (3) ◽

pp. 303-311 ◽

Cited By ~ 6

Author(s):

V. F. Kopiev ◽

M. Yu. Zaitsev ◽

S. I. Inshakov ◽

L. P. Guriashkin

Keyword(s):

Large Scale ◽

Turbulent Jets ◽

Vortex Structures ◽

Large Scale Vortex

Download Full-text

3D dynamical structuring of a high latitude erupting prominence: I- Analysis of the cool plasma flows before the eruption

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313011411 ◽

2013 ◽

Vol 8 (S300) ◽

pp. 430-432

Author(s):

Serge Koutchmy ◽

Boris Filippov ◽

Ehsan Tavabi ◽

Cyril Bazin ◽

Sylvain Weiller

Keyword(s):

Magnetic Field ◽

High Latitude ◽

Large Scale ◽

Vortex Structures ◽

Small Scale ◽

Plasma Flows ◽

Cool Plasma ◽

Large Scale Vortex ◽

Good Proxy

AbstractBoth the origin of the quiescent prominences and their eruption related to CMEs are still a matter of extended studies. The small scale dynamic aspects like vortex structures and counter- flows are now seriously taken into account having in mind that the flows are a good proxy of the line of force of the omnipresent but rather unknown in detail force free or not magnetic field. Large scale vortex has been detected in a high latitude prominence observed on November 13- 14, 2011 before its eruption.

Download Full-text