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We have shown that the epsilon-entropy determined from the time-series of the velocity fluctuation in a forced turbulence simulated by the lattice Boltzmann method obeys the Kolmogorov scaling.

Statistical Mechanics · Physics 2007-05-23 W. Sakikawa , O. Narikiyo

We conduct experiments in a turbulent bubbly flow to study the nature of the transition between the classical $-$5/3 energy spectrum scaling for a single-phase turbulent flow and the $-$3 scaling for a swarm of bubbles rising in a quiescent…

Direct numerical simulations are used to investigate the individual dynamics of large spherical particles suspended in a developed homogeneous turbulent flow. A definition of the direction of the particle motion relative to the surrounding…

Fluid Dynamics · Physics 2015-06-16 Mamadou Cisse , Holger Homann , Jeremie Bec

We study scalar bubble collisions in first-order phase transitions focusing on the relativistic limit. We propose 'trapping equation' which describes the wall behavior after collision, and test it with numerical simulations in several…

High Energy Physics - Phenomenology · Physics 2020-09-16 Ryusuke Jinno , Thomas Konstandin , Masahiro Takimoto

We describe and implement a technique for extracting forces from the relaxation of an overdamped thermal system with normal modes. At sufficiently short time intervals, the evolution of a normal mode is well described by a one-dimensional…

Soft Condensed Matter · Physics 2009-11-13 Sunil K. Sainis , Vincent Germain , Eric R. Dufresne

An experimental study was conducted in the CICLoPE long-pipe facility to investigate the correlation between wall-pressure and turbulent velocity fluctuations in the logarithmic region, at high friction Reynolds numbers ($4\,794 \lesssim…

In the current work we construct a multimolecule random process which leads to the Boltzmann equation in the appropriate limit, and which is different from the deterministic real gas dynamics process. We approximate the statistical…

Fluid Dynamics · Physics 2017-05-30 Rafail V. Abramov

Recently the general form of a translation-covariant quantum Boltzmann equation has been derived which describes the dynamics of a tracer particle in a quantum gas. We develop a stochastic wave function algorithm that enables full…

Quantum Physics · Physics 2007-09-24 Heinz-Peter Breuer , Bassano Vacchini

The turbulent flow within and above a sparse canopy is investigated using direct numerical simulations. The balance of Reynolds to viscous stresses within the canopy is observed to be similar to that over a smooth wall. From this, a scaling…

Fluid Dynamics · Physics 2018-10-25 Akshath Sharma , Ricardo García-Mayoral

Various experiments have found a boundary slip in hydrophobic microchannel flows, but a consistent understanding of the results is still lacking. While Molecular Dynamics (MD) simulations cannot reach the low shear rates and large system…

Fluid Dynamics · Physics 2007-05-23 Jens Harting , Christian Kunert , Hans J. Herrmann

When the flow is sufficiently rarefied, a temperature gradient, for example, between two walls separated by a few mean free paths, induces a gas flow---an observation attributed to the thermo-stress convection effects at microscale. The…

Accurate and economical modeling of near-surface transport processes is a standing challenge for various engineering and atmospheric boundary-layer flows. In this paper, we address this challenge by utilizing a stochastic one-dimensional…

Fluid Dynamics · Physics 2021-12-01 Marten Klein , Heiko Schmidt , David O. Lignell

This work reports an experimental characterisation of the flow properties in a homogeneous bubble swarm rising at high-Reynolds-numbers within a homogeneous and isotropic turbulent flow. Both the gas volume fraction {\alpha} and the…

Fluid Dynamics · Physics 2017-10-11 Elise Almeras , Varghese Mathai , Detlef Lohse , Chao Sun

The phenomenon of apparent slip in micro-channel flows is analyzed by means of a two-phase mesoscopic lattice Boltzmann model including non-ideal fluid-fluid and fluid-wall interactins. The weakly-inhomogeneous limit of this model is solved…

Fluid Dynamics · Physics 2016-09-08 R. Benzi , L. Biferale , M. Sbragaglia , S. Succi , F. Toschi

We present a mesoscopic model, based on the Boltzmann Equation, for the interaction between a solid wall and a non-ideal fluid. We present an analytic derivation of the contact angle in terms of the surface tension between the liquid-gas,…

Chaotic Dynamics · Physics 2007-06-13 R. Benzi , L. Biferale , M. Sbragaglia , S. Succi , F. Toschi

Large scale simulations of two-dimensional bidisperse granular fluids allow us to determine spatial correlations of slow particles via the four-point structure factor $S_4(q,t)$. Both cases, elastic ($\varepsilon=1$) as well as inelastic…

Statistical Mechanics · Physics 2014-07-16 Karina E. Avila , Horacio E. Castillo , Andrea Fiege , Katharina Vollmayr-Lee , Annette Zippelius

The derivation of shallow water models from Navier-Stokes equations is revisited yielding a class of two-layer shallow water models.An improved velocity profile is proposed, based on the superposition of an ideal fluid and a viscous layer…

Analysis of PDEs · Mathematics 2018-06-11 François James , Pierre-Yves Lagrée , Hoang-Minh Le , Mathilde Legrand

The space-time dynamics of rigid inhomogeneities (inclusions) free to move in a randomly fluctuating fluid bio-membrane is derived and numerically simulated as a function of the membrane shape changes. Both vertically placed (embedded)…

Computational Physics · Physics 2007-05-23 H. Rafii-Tabar , H. R. Sepangi

We describe numerical simulations of the critical dynamics near the superfluid phase transition. The calculations are based on an implementation of a stochastic hydrodynamic theory known as model F in the classification of Hohenberg and…

Liquid-solid phase transition and the change of the frictional force of a system with two hard spheres in a two-dimensional rectangular box are discussed. Under controlling the pressure or the supply of energy from the wall, the solid like…

Condensed Matter · Physics 2007-05-23 A. Awazu