Vortex Dynamics in Turbulence

Pullin, D. I.; Saffman, P. G.

doi:10.1146/annurev.fluid.30.1.31

Cited by 130 publications

(102 citation statements)

References 85 publications

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“…Following the 'vortex string' conceptualization of eddies -that eddies are long rotating bodies of fluid (Pullin and Saffman, 1998) -the eddy volume can be calculated as:…”

Section: Discussionmentioning

confidence: 99%

The effects of turbulent eddies on the stability and critical swimming speed of creek chub (Semotilus atromaculatus)

Tritico

Cotel

2010

Journal of Experimental Biology

194

197

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SUMMARYThe effect of turbulent eddy diameter, vorticity and orientation on the 2min critical swimming speed and stability of creek chub (Semotilus atromaculatus) is reported. Turbulent eddies were visualized and their properties were quantified using particle image velocimetry (PIV). Flow fields with an increasing range in eddy diameter were created by inserting cylinder arrays upstream from the swimming test section. Eddy vorticity increased with increasing velocity. Two orientations of eddies, eddies spinning about a vertical axis and eddies spinning about a horizontal (wall-to-wall) axis, were investigated. Stability challenges were not observed until the largest (95th percentile) eddy diameters reached 76% of the fish body total length. Under these conditions fish were observed to spin in an orientation consistent with the rotational axis of the large eddies and translate downstream. These losses in postural control were termed 'spills'. Spills were 230% more frequent and lasted 24% longer in turbulent flow fields dominated by horizontal eddies than by vertical eddies of the same diameter. The onset of spills coincided with a 10% and 22% reduction in critical swimming speed in turbulent flows dominated by large vertical and horizontal eddies, respectively. These observations confirm predictions by Pavlov et al., Cada and Odeh, Lupandin, and Liao that the eddy diameter, vorticity and orientation play an important role in the swimming capacity of fishes.

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“…Following the 'vortex string' conceptualization of eddies -that eddies are long rotating bodies of fluid (Pullin and Saffman, 1998) -the eddy volume can be calculated as:…”

Section: Discussionmentioning

confidence: 99%

The effects of turbulent eddies on the stability and critical swimming speed of creek chub (Semotilus atromaculatus)

Tritico

Cotel

2010

Journal of Experimental Biology

194

197

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“…Batchelor 1967;Saffman 1992). In particular, intermittency in high-Reynolds-number turbulence has been hypothesized to be related to the organized vortical structures with candidate tube-like or sheet-like geometries (see Pullin & Saffman 1998). In a general sense, an open or closed 'vortex surface' can be defined as a smooth surface or manifold embedded within a three-dimensional velocity field, which has the property that the local vorticity vector is tangent at every point on the surface.…”

Section: Introductionmentioning

confidence: 99%

Evolution of vortex-surface fields in viscous Taylor–Green and Kida–Pelz flows

Yang

Pullin

2011

J. Fluid Mech.

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In order to investigate continuous vortex dynamics based on a Lagrangian-like formulation, we develop a theoretical framework and a numerical method for computation of the evolution of a vortex-surface field (VSF) in viscous incompressible flows with simple topology and geometry. Equations describing the continuous, timewise evolution of a VSF from an existing VSF at an initial time are first reviewed. Non-uniqueness in this formulation is resolved by the introduction of a pseudo-time and a corresponding pseudo-evolution in which the evolved field is 'advected' by frozen vorticity onto a VSF. A weighted essentially non-oscillatory (WENO) method is used to solve the pseudo-evolution equations in pseudo-time, providing a dissipativelike regularization. Vortex surfaces are then extracted as iso-surfaces of the VSFs at different real physical times. The method is applied to two viscous flows with Taylor-Green and Kida-Pelz initial conditions respectively. Results show the collapse of vortex surfaces, vortex reconnection, the formation and roll-up of vortex tubes, vorticity intensification between anti-parallel vortex tubes, and vortex stretching and twisting. A possible scenario for understanding the transition from a smooth laminar flow to turbulent flow in terms of topology of vortex surfaces is discussed.

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“…Having in mind these (important) caveats, in this article, we employ B and ω as the most appropriate pair of gauge and inertial fields whose structural interactions can lead to a "synthetic" understanding of more complicated MHD turbulence processes. In doing so, we follow a long tradition in turbulence theory [14][15][16][17], that is complementary to other statistical approaches [18,19]. Inspired by fully resolved Navier-Stokes turbulence results, we choose a straight vortex tube as a rough model of turbulence structure.…”

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confidence: 99%

Interactions between vortex tubes and magnetic-flux rings at high kinetic and magnetic Reynolds numbers

Kivotides

2018

Phys. Rev. Fluids

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The interactions between vortex tubes and magnetic-flux rings in incompressible MHD are inves- [MHD]), and, via its convection by the velocity field, becomes turbulent, developing coherent structures of its own. Thus, it is conceptually important to understand the interactions between structures in the gauge and inertial fields, and the way these can help understand (in a structural way) some of the complexity of turbulent chaos, (b) the presence of the Lorentz force in the Navier-Stokes equations enables the depiction of wave phenomena in the latter (Alfven waves), which lead to novel (in comparison with incompressible turbulence)

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Vortex Dynamics in Turbulence

Cited by 130 publications

References 85 publications

The effects of turbulent eddies on the stability and critical swimming speed of creek chub (Semotilus atromaculatus)

The effects of turbulent eddies on the stability and critical swimming speed of creek chub (Semotilus atromaculatus)

Evolution of vortex-surface fields in viscous Taylor–Green and Kida–Pelz flows

Interactions between vortex tubes and magnetic-flux rings at high kinetic and magnetic Reynolds numbers

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