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We study the dynamics of neutrally buoyant particles with diameters varying in the range [1, 45] in Kolmogorov scale units (eta) and Reynolds numbers based on Taylor scale between 580 and 1050. One component of the particles' velocity is…

Fluid Dynamics · Physics 2011-09-02 Romain Volk , Enrico Calzavarini , Emmanuel Leveque , Jean-Francois Pinton

The nonextensive statistical ensembles are revisited for the complex systems with long-range interactions and long-range correlations. An approximation, the value of nonextensive parameter (1-q) is assumed to be very tiny, is adopted for…

Statistical Mechanics · Physics 2020-02-26 Yahui Zheng , Jiulin Du , Linxia Liu , Huijun Kong

This article proposes a Reynolds number scaling of the required grid points to perform wall-modeled LES of turbulent flows encountering separation off a solid surface. Based on comparisons between the various time scales in a…

Fluid Dynamics · Physics 2024-01-02 Rahul Agrawal , Sanjeeb Bose , Parviz Moin

The statistical properties of heavy particle trajectories in high Reynolds numbers turbulent flows are analyzed. Dimensional analysis assuming Kolmogorov scaling is compared with the result of numerical simulation using a synthetic…

Chaotic Dynamics · Physics 2009-11-07 Piero Olla

We extend the ideas of Kolmogorov theory on symmetries of turbulent dynamics to analyze invariants, scaling and spectra of unsteady turbulent mixing induced by the Rayleigh-Taylor instability. Time- and scale-invariance of the rate of…

Plasma Physics · Physics 2010-04-28 Snezhana I. Abarzhi

We study the fine-scale statistics of temperature and its derivatives in turbulent Rayleigh-Benard convection. Direct numerical simulations are carried out in a cylindrical cell with unit aspect ratio filled with a fluid with Prandtl number…

Fluid Dynamics · Physics 2015-05-13 M. S. Emran , J. Schumacher

Turbulence -- ubiquitous in nature and engineering alike [1-5] -- is traditionally viewed as an intrinsically inertial phenomenon, emerging only when the Reynolds number (Re), which quantifies the ratio of inertial to dissipative forces…

Fluid Dynamics · Physics 2025-11-11 Ziyue Yu , Xinyu Si , Lei Fang

We study the nonextensive parameter for the rotating astrophysical systems with power-law distributions, including both the rotating self-gravitating system and the rotating space plasma. We extend the equation of nonextensive parameter to…

Statistical Mechanics · Physics 2017-02-10 Haining Yu , Jiulin Du

We investigate the instability and nonlinear saturation of temperature-stratified Taylor-Couette flows in a finite height cylindrical gap and calculate angular-momentum transport in the nonlinear regime. The model is based on an…

Astrophysics · Physics 2009-11-13 M. Gellert , G. Rüdiger

The research is devoted to the stability of convective flow in a nonuniformly rotating layer of an electrically conducting fluid in a spiral magnetic field. The stationary and oscillatory modes of magnetic convection are considered…

Plasma Physics · Physics 2019-05-15 M. I. Kopp , A. V. Tur , V. V. Yanovsky

Aims: To investigate the stability and angular momentum transport by the strato-rotational instability in the nonlinear regime. Methods: The hydrodynamic compressible equations are solved in a cartesian box in which the outer cylinder is…

Astrophysics · Physics 2007-05-23 A. Brandenburg , G. Ruediger

We study the stability of the Couette-Taylor flow between porous cylinders with radial throughflow. It had been shown earlier that this flow can be unstable with respect to non-axisymmetric (azimuthal or helical) waves provided that the…

Fluid Dynamics · Physics 2019-12-02 Konstantin Ilin , Andrey Morgulis

This study aims to investigate the possible sources of non-axisymmetric disturbances and their propagation mechanism in Taylor Couette flow (TCF) for wide gap problems using direct numerical simulation with a radius ratio of 0.5 and…

Fluid Dynamics · Physics 2019-08-26 Md Abdur Razzak , Boo Cheong Khoo , Kim Boon Lua

We propose a model for the streamwise velocity variance in wall-bounded turbulent flows. It hypothesizes that the wall-parallel motions of the attached eddies induce internal turbulent boundary layers. A logarithmic variance profile is…

Fluid Dynamics · Physics 2024-05-07 Chenning Tong

In this work, we prove what appear to be the first Reynolds-semi-robust and pressure-robust velocity error estimates for an H(div)-conforming approximation of unsteady incompressible flows of power-law type fluids. The proposed methods…

Numerical Analysis · Mathematics 2025-05-14 Lourenço Beirão da Veiga , Daniele A. Di Pietro , Kirubell B. Haile

A turbulent pipe flow experiment was conducted where the surface of the pipe was oscillated azimuthally over a wide range of frequencies, amplitudes and Reynolds number. The drag was reduced by as much as 30\%. Past work has suggested that…

Fluid Dynamics · Physics 2024-02-06 Liuyang Ding , Lena Sabidussi , Brian C. Holloway , Marcus Hultmark , Alexander J. Smits

Dry, wet, dense, and dilute granular flows have been previously considered fundamentally different and thus described by distinct, and in many cases incompatible, rheologies. We carry out extensive simulations of granular flows, including…

Soft Condensed Matter · Physics 2019-09-17 Thomas Pähtz , Orencio Durán , David N. de Klerk , Indresan Govender , Martin Trulsson

Polymers in nonuniform flows undergo strong deformation, which in the presence of persistent stretching can result in the coil-stretch transition. This phenomenon has been characterized by using the formalism of nonequilibrium statistical…

Soft Condensed Matter · Physics 2023-05-24 Stefano Musacchio , Victor Steinberg , Dario Vincenzi

We investigate the nonextensivity and the q-distribution of a relativistic gas under an external electromagnetic field. We derive a formula expression of the nonextensive parameter q based on the relativistic generalized Boltzmann equation,…

Statistical Mechanics · Physics 2015-08-10 Zhipeng Liu , Jiulin Du , Lina Guo

We introduce a new heterogeneous multi-scale method for the simulation of flows of non-Newtonian fluids in general geometries and present its application to paradigmatic two-dimensional flows of polymeric fluids. Our method combines…