Journal ArticleDOI
The structure of intense vorticity in isotropic turbulence
TLDR
In this paper, the structure of the intense-vorticity regions is studied in numerically simulated homogeneous, isotropic, equilibrium turbulent flow fields at four different Reynolds numbers, in the range Re, = 35-170.Abstract:
The structure of the intense-vorticity regions is studied in numerically simulated homogeneous, isotropic, equilibrium turbulent flow fields at four different Reynolds numbers, in the range Re, = 35-170. In accordance with previous investigators this vorticity is found to be organized in coherent, cylindrical or ribbon-like, vortices (‘worms’). A statistical study suggests that they are simply especially intense features of the background, O(o’), vorticity. Their radii scale with the Kolmogorov microscale and their lengths with the integral scale of the flow. An interesting observation is that the Reynolds number y/v, based on the circulation of the intense vortices, increases monotonically with ReA, raising the question of the stability of the structures in the limit of Re, --z co. Conversely, the average rate of stretching of these vortices increases only slowly with their peak vorticity, suggesting that self-stretching is not important in their evolution. One- and two-dimensional statistics of vorticity and strain are presented; they are non-Gaussian and the behaviour of their tails depends strongly on the Reynolds number. There is no evidence of convergence to a limiting distribution in this range of Re,, even though the energy spectra and the energy dissipation rate show good asymptotic properties in the higher-Reynolds-number cases. Evidence is presented to show that worms are natural features of the flow and that they do not depend on the particular forcing scheme.read more
Citations
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DIRECT NUMERICAL SIMULATION: A Tool in Turbulence Research
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TL;DR: In this article, direct numerical simulation (DNS) of turbulent flows has been reviewed and the complementary nature of experiments and computations in turbulence research has been illustrated, as well as how DNS has impacted turbulence modeling and provided further insight into the structure of turbulent boundary layers.
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The phenomenology of small-scale turbulence
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A Lagrangian dynamic subgrid-scale model of turbulence
TL;DR: In this paper, the Smagorinsky eddy-viscosity model is combined with a spatially averaged dynamic model for complex-geometry inhomogeneous flows, and a new dynamic model formulation is introduced that combines advantages of the statistical and local approaches.
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New Trends in Large-Eddy Simulations of Turbulence
Marcel Lesieur,Olivier Métais +1 more
TL;DR: In this article, a large-eddy simulation (LES) formalism, along with various subgrid-scale models developed since Smagorinsky's model, is presented, with an emphasis on the generation of coherent vortices.
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Scaling of the velocity fluctuations in turbulent channels up to Reτ=2003
Sergio Hoyas,Javier Jiménez +1 more
TL;DR: In this article, a new numerical simulation of a turbulent channel in a large box at Reτ=2003 is described and briefly compared with simulations at lower Reynolds numbers and with experiments.
References
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Journal Article
The Local Structure of Turbulence in Incompressible Viscous Fluid for Very Large Reynolds' Numbers
TL;DR: In this article, the authors consider the problem of finding the components of the velocity at every point of a point with rectangular cartesian coordinates x 1, x 2, x 3, x 4, x 5, x 6, x 7, x 8.
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The theory of homogeneous turbulence
TL;DR: In this article, the kinematics of the field of homogeneous turbulence and the universal equilibrium theory of decay of the energy-containing eddies are discussed. But the authors focus on the dynamics of decay and not on the probability distribution of u(x).
Journal ArticleDOI
Simple Eulerian time correlation of full-and narrow-band velocity signals in grid-generated, ‘isotropic’ turbulence
TL;DR: In this paper, the Eulerian time correlation coefficient of turbulent velocities passed through matched narrow-band niters shows a strong dependence on nominal filter frequency (∼ wave-number at these small turbulence levels).
Journal ArticleDOI
The spatial structure and statistical properties of homogeneous turbulence
A. Vincent,M. Meneguzzi +1 more
TL;DR: In this article, the authors used a direct numerical simulation at resolution 2403 to obtain a statistically stationary three-dimensional homogeneous and isotropic turbulent field at a Reynolds number around 1000 (Rλ ≈ 150).
Journal ArticleDOI
Alignment of vorticity and scalar gradient with strain rate in simulated Navier-Stokes turbulence
TL;DR: In this paper, the alignment between vorticity and eigenvectors of the strain-rate tensor in numerical solutions of Navier-Stokes turbulence is studied, and the authors show that the relationship between the velocity and the energy dissipation is a power-law relation between conditioned mean values.
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