scholarly journals Spatial velocity correlations in inertial systems of active Brownian particles

Soft Matter ◽  
2021 ◽  
Vol 17 (15) ◽  
pp. 4109-4121 ◽  
Author(s):  
Lorenzo Caprini ◽  
Umberto Marini Bettolo Marconi
Keyword(s):  
Velocity Field ◽  
Thermal Diffusion ◽  
Coherent Structures ◽  
Peclet Number ◽  
High Density ◽  
Equilibrium Behavior ◽  
Brownian Particles ◽  
Spatial Velocity ◽  
Inertial Systems ◽  
Non Equilibrium

The velocity field of systems of active Brownian particles at high density shows large spatial coherent structures, a genuine non-equilibrium behavior. The effects of Peclet number, inertia and thermal diffusion on the ordering phenomenon are studied.

An approximate quantitative analysis of non-equilibrium plasma transport for high density plasmas

1995 ◽  
Vol 16 (S1) ◽  
pp. S19-S42 ◽  
Author(s):  
D. C. Schram ◽  
J. C. M. de Haas ◽  
J. A. M. van der Mullen ◽  
M. C. M. van de Sanden
Keyword(s):  
Quantitative Analysis ◽  
High Density ◽  
Plasma Transport ◽  
Equilibrium Plasma ◽  
Non Equilibrium

Non-Equilibrium Molecular Dynamics Study of the Influence of Branching on the Soret Coefficient of Binary Mixtures of Heptane Isomers

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaoyu Chen ◽  
Ruquan Liang ◽  
Lichun Wu ◽  
Gan Cui
Keyword(s):  
Molecular Dynamics ◽  
Thermal Diffusion ◽  
Soret Coefficient ◽  
Isomer Mixture ◽  
Acentric Factor ◽  
Diffusion Behavior ◽  
The Difference ◽  
Non Equilibrium Molecular Dynamics ◽  
Molecular Branching ◽  
Non Equilibrium

Abstract Equimolar mixtures composed of isomers were firstly used to investigate the molecular branching effect on thermal diffusion behavior, which was not disturbed by factors of molecular mass and composition in this work. Eight heptane isomers, including n-heptane, 2-methylhexane, 3-methylhexane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane and 3-ethylpentane, were chosen as the researched mixtures. A non-equilibrium molecular dynamics (NEMD) simulation with enhanced heat exchange (eHEX) algorithm was applied to calculate the Soret coefficient at T = 303.15 T=303.15  K and P = 1.0 atm P=1.0\hspace{0.1667em}\text{atm} . An empirical correlation based on an acentric factor was proposed and its calculation coincides with the simulated results, which showed the validity of the NEMD simulation. It is demonstrated that the isomer with higher acentric factor has a stronger thermophilic property and tends to migrate to the hot region in the heptane isomer mixture, and the extent of thermal diffusion is proportional to the difference between the acentric factors of the isomers.

Determination of spatial velocity dispersion profile and stream velocity field in galaxy clusters - Application to Coma

1982 ◽  
Vol 252 ◽  
pp. 433 ◽  
Author(s):  
H. V. Capelato ◽  
D. Gerbal ◽  
G. Mathez ◽  
A. Mazure ◽  
E. Salvador-Sole
Keyword(s):  
Velocity Field ◽  
Galaxy Clusters ◽  
Velocity Dispersion ◽  
Stream Velocity ◽  
Dispersion Profile ◽  
Spatial Velocity

scholarly journals Pollution Transport Patterns Obtained Through Generalized Lagrangian Coherent Structures

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 168
Author(s):  
Peter J. Nolan ◽  
Hosein Foroutan ◽  
Shane D. Ross
Keyword(s):  
Velocity Field ◽  
Coherent Structures ◽  
Initial Conditions ◽  
Saddle Points ◽  
Chemical Species ◽  
Lagrangian Coherent Structures ◽  
Time Interval ◽  
Pollution Transport ◽  
Material Transport ◽  
Material Surfaces

Identifying atmospheric transport pathways is important to understand the effects of pollutants on weather, climate, and human health. The atmospheric wind field is variable in space and time and contains complex patterns due to turbulent mixing. In such a highly unsteady flow field, it can be challenging to predict material transport over a finite-time interval. Particle trajectories are often used to study how pollutants evolve in the atmosphere. Nevertheless, individual trajectories are sensitive to their initial conditions. Lagrangian Coherent Structures (LCSs) have been shown to form the template of fluid parcel motion in a fluid flow. LCSs can be characterized by special material surfaces that organize the parcel motion into ordered patterns. These key material surfaces form the core of fluid deformation patterns, such as saddle points, tangles, filaments, barriers, and pathways. Traditionally, the study of LCSs has looked at coherent structures derived from integrating the wind velocity field. It has been assumed that particles in the atmosphere will generally evolve with the wind. Recent work has begun to look at the motion of chemical species, such as water vapor, within atmospheric flows. By calculating the flux associated with each species, a new effective flux-based velocity field can be obtained for each species. This work analyzes generalized species-weighted coherent structures associated with various chemical species to find their patterns and pathways in the atmosphere, providing a new tool and language for the assessment of pollutant transport and patterns.

Resonance dynamics in compressible cavity flows using time-resolved velocity and surface pressure fields

2017 ◽  
Vol 830 ◽  
pp. 494-527 ◽  
Author(s):  
Justin L. Wagner ◽  
Steven J. Beresh ◽  
Katya M. Casper ◽  
Edward P. DeMauro ◽  
Srinivasan Arunajatesan
Keyword(s):  
Velocity Field ◽  
Shear Layer ◽  
Surface Pressure ◽  
Coherent Structures ◽  
Acoustic Waves ◽  
Mode Switching ◽  
Recirculation Region ◽  
Mean Flow ◽  
Time Resolved ◽  
Phase Velocities

The resonance modes in Mach 0.94 turbulent flow over a cavity having a length-to-depth ratio of five were explored using time-resolved particle image velocimetry (TR-PIV) and time-resolved pressure sensitive paint (TR-PSP). Mode switching was quantified in the velocity field simultaneous with the pressure field. As the mode number increased from one through three, the resonance activity moved from a region downstream within the recirculation region to areas further upstream in the shear layer, an observation consistent with linear stability analysis. The second and third modes contained organized structures associated with shear layer vortices. Coherent structures occurring in the velocity field during modes two and three exhibited a clear modulation in size with streamwise distance. The streamwise periodicity was attributable to the interference of downstream-propagating vortical disturbances with upstream-travelling acoustic waves. The coherent structure oscillations were approximately $180^{\circ }$ out of phase with the modal surface pressure fluctuations, analogous to a standing wave. Modal propagation (or phase) velocities, based on cross-correlations of bandpass-filtered velocity fields were found for each mode. The phase velocities also showed streamwise periodicity and were greatest at regions of maximum constructive interference where coherent structures were the largest. Overall, the phase velocities increased with modal frequency, which coincided with the modal activity residing at higher portions of the cavity where the local mean flow velocity was elevated. Together, the TR-PIV and TR-PSP provide unique details not only on the distribution of modal activity throughout the cavity, but also new understanding of the resonance mechanism as observed in the velocity field.

Non-equilibrium behavior of small carbohydrate-water systems

1988 ◽  
Vol 60 (12) ◽  
pp. 1841-1864 ◽  
Author(s):  
L. Slade ◽  
Harry Levine
Keyword(s):  
Water Systems ◽  
Equilibrium Behavior ◽  
Non Equilibrium
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