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Topological defects in systems with liquid-crystalline order are crucial in determining their large-scale properties. In active systems, they are known to have properties impossible at equilibrium: for example, $+1/2$ defects in…

Soft Condensed Matter · Physics 2026-02-17 Giacomo Marco La Montagna , Sumeja Burekovic , Ananyo Maitra , Cesare Nardini

Turbulent motions due to flux-driven thermal convection is investigated by numerical simulations and stochastic modelling. Tilting of convection cells leads to the formation of sheared flows and quasi-periodic relaxation oscillations for…

Fluid Dynamics · Physics 2020-08-26 G. Decristoforo , A. Theodorsen , O. E. Garcia

We study diffusive mixing in the presence of thermal fluctuations under the assumption of large Schmidt number. In this regime we obtain a limiting equation that contains a diffusive thermal drift term with diffusion coefficient obeying a…

Statistical Mechanics · Physics 2015-06-18 A. Donev , T. G. Fai , E. Vanden-Eijnden

We report numerical results on the velocity statistics of topological defects during the dynamics of phase ordering and non-relaxational evolution assisted by an external shear ow. We propose a numerically efficient tracking method for…

Statistical Mechanics · Physics 2015-06-03 Luiza Angheluta , Patricio Jeraldo , Nigel Goldenfeld

We consider the transport of passive admixture in locally homogeneous isotropic reflectionally noninvariant turbulence of incompressible fluid. It is shown that anomalous convective flow appears which direction does not coincide with that…

chao-dyn · Physics 2008-02-03 A. V. Chechkin , A. V. Tur , V. V. Yanovsky

The velocity fluctuations for point vortex models are studied for the {\alpha}-turbulence equations, which are characterized by a fractional Laplacian relation between active scalar and the streamfunction. In particular, we focus on the…

Fluid Dynamics · Physics 2019-09-11 Giovanni Conti , Gualtiero Badin

It was found in [Europhysics Letters {\bf 104}, (2013), 60003] that classical Tsallis theory exhibits poles in the partition function ${\cal Z}$ and the mean energy $<{\cal U}>$. These occur at a countably set of the q-line. We give here,…

Statistical Mechanics · Physics 2016-11-15 M. C. Rocca , A. Plastino , G. L. Ferri

We establish a theoretical framework for predicting friction and heat transfer coefficients in variable-properties forced air convection. Drawing from concepts in high-speed wall turbulence, which also involves significant temperature,…

Fluid Dynamics · Physics 2024-12-18 Davide Modesti , Sergio Pirozzoli

In Ref. [1] the statistical structure of the turbulent cascade in the context of non-additive entropy was considered. Here we suggest that the vortex line ensemble in the Vinen quantum turbulence in superfluids is described by the…

Statistical Mechanics · Physics 2026-04-28 G. E. Volovik

The large scale turbulent statistics of mechanically driven superfluid $^4$He was shown experimentally to follow the classical counterpart. In this paper we use direct numerical simulations to study the whole range of scales in a range of…

Other Condensed Matter · Physics 2018-02-28 L. Biferale , D. Khomenko , V. L'vov , A. Pomyalov , I. Procaccia , G. Sahoo

The probability density function (PDF) of accelerations in turbulence is derived analytically with the help of the multifractal analysis based on generalized entropy, i.e., the Tsallis or the R\'{e}nyi entropy. It is shown that the derived…

Statistical Mechanics · Physics 2007-05-23 T. Arimitsu , N. Arimitsu

We study the topological configurations and dynamics of individual point defect vacancies and interstitials in a two-dimensional colloidal crystal. Our Brownian dynamics simulations show that the diffusion mechanism for vacancy defects…

Soft Condensed Matter · Physics 2009-11-11 A. Libal , C. Reichhardt , C. J. Olson Reichhardt

We consider a generalized statistical mechanics model for the creation process of cosmic rays which takes into account local temperature fluctuations. This model yields Tsallis statistics for the cosmic ray spectrum. It predicts an entropic…

Statistical Mechanics · Physics 2015-06-24 Christian Beck

In this paper we present a study of anomalous diffusion using a Fokker-Planck description with fractional velocity derivatives. The distribution functions are found using numerical means for varying degree of fractionality observing the…

Plasma Physics · Physics 2014-12-18 Johan Anderson , Eun-jin Kim , Sara Moradi

Using experimental data on thermal convection, obtained at a Rayleigh number of 1.5 $\times 10^{11}$, it is shown that the temperature structure functions $<\Delta T_{r}^p>$, where $\Delta T_r$ is the absolute value of the temperature…

Chaotic Dynamics · Physics 2009-11-11 A. Bershadskii , K. R. Sreenivasan , J. J. Niemela

In this short paper, we establish a variational expression of the Tsallis relative entropy. In addition, we derive a generalized thermodynamic inequality and a generalized Peierls-Bogoliubov inequality. Finally we give a generalized…

Statistical Mechanics · Physics 2010-01-10 Shigeru Furuichi

The buoyancy-induced parallel flow in a vertical cylindrical porous layer is analysed. A radial thermal gradient caused by a uniformly distributed heat source is assumed to induce the buoyant flow. The layer boundaries are modelled as…

Fluid Dynamics · Physics 2023-02-03 A. Barletta , D. A. S. Rees , B. Pulvirenti

The article demonstrates that the internal circulation velocity and patterns in sessile droplets on superhydrophobic surfaces is governed by the surface curvature. Particle Image Velocimetry reveals that increasing convexity deteriorates…

Fluid Dynamics · Physics 2018-06-15 Gargi Khurana , A R Harikrishnan , Vivek Jaiswal , Purbarun Dhar

We study the dynamics of topological defects in continuum theories governed by a free energy minimization principle, building on our recently developed framework [Romano J, Mahault B and Golestanian R 2023 J. Stat. Mech.: Theory Exp.…

Soft Condensed Matter · Physics 2024-02-26 Jacopo Romano , Benoît Mahault , Ramin Golestanian

Thermal conductance has emerged as a powerful probe of topological order in the quantum Hall effect and beyond. The interpretation of experiments crucially depends on the ratio of the sample size and the equilibration length, on which…

Mesoscale and Nanoscale Physics · Physics 2020-07-07 Ken K. W. Ma , D. E. Feldman