Lyapunov spectra and conjugate-pairing rule for confined atomic fluids

被引:9
作者
Bernardi, Stefano [1 ]
Todd, B. D. [1 ]
Hansen, J. S. [2 ]
Searles, Debra J. [3 ,4 ]
Frascoli, Federico [5 ]
机构
[1] Swinburne Univ Technol, Ctr Mol Simulat, Hawthorn, Vic 3122, Australia
[2] Roskilde Univ Ctr, IMFUFA, DNRF Ctr Glass & Time, DK-4000 Roskilde, Denmark
[3] Griffith Univ, Sch Biomol & Phys Sci, Brisbane, Qld 4111, Australia
[4] Griffith Univ, Queensland Micro & Nanotechnol Ctr, Brisbane, Qld 4111, Australia
[5] Swinburne Univ Technol, Brain Sci Inst, Hawthorn, Vic 3122, Australia
关键词
NONEQUILIBRIUM MOLECULAR-DYNAMICS; SPACE DIMENSIONALITY LOSS; TRANSPORT-COEFFICIENTS; FLUCTUATION THEOREM; SHEAR VISCOSITY; STEADY-STATES; EXPONENTS; SYSTEMS; EQUILIBRIUM; MODEL;
D O I
10.1063/1.3446809
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
In this work we present nonequilibrium molecular dynamics simulation results for the Lyapunov spectra of atomic fluids confined in narrow channels of the order of a few atomic diameters. We show the effect that realistic walls have on the Lyapunov spectra. All the degrees of freedom of the confined system have been considered. Two different types of flow have been simulated: planar Couette flow and planar Poiseuille flow. Several studies exist on the former for homogeneous flows, so a direct comparison with previous results is performed. An important outcome of this work is the demonstration of how the spectrum reflects the presence of two different dynamics in the system: one for the unthermostatted fluid atoms and the other one for the thermostatted and tethered wall atoms. In particular the Lyapunov spectrum of the whole system does not satisfy the conjugate-pairing rule. Two regions are instead distinguishable, one with negative pairs' sum and one with a sum close to zero. To locate the different contributions to the spectrum of the system, we computed "approximate" Lyapunov exponents belonging to the phase space generated by the thermostatted area and the unthermostatted area alone. To achieve this, we evolved Lyapunov vectors projected into a reduced dimensional phase space. We finally observe that the phase-space compression due to the thermostat remains confined into the wall region and does not significantly affect the purely Newtonian fluid region. (C) 2010 American Institute of Physics. [doi:10.1063/1.3446809]
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页数:11
相关论文
共 53 条
[1]  
[Anonymous], 2008, STAT MECH NONEQUILIB
[2]   Lyapunov exponents and the extensivity of dimensional loss for systems in thermal gradients [J].
Aoki, K ;
Kusnezov, D .
PHYSICAL REVIEW E, 2003, 68 (05)
[3]  
Benettin G., 1980, Meccanica, V15, P21, DOI 10.1007/BF02128237
[4]  
Benettin Giancarlo, 1980, Meccanica, V15, P9, DOI DOI 10.1007/BF02128236
[5]  
Bird R. B., 1987, FLUID MECH-SOV RES, V2nd
[6]   On the validity of the conjugate pairing rule for Lyapunov exponents [J].
Bonetto, F ;
Cohen, EGD ;
Pugh, C .
JOURNAL OF STATISTICAL PHYSICS, 1998, 92 (3-4) :587-627
[7]   The shear viscosity of molecular fluids:: A calculation by reverse nonequilibrium molecular dynamics [J].
Bordat, P ;
Müller-Plathe, F .
JOURNAL OF CHEMICAL PHYSICS, 2002, 116 (08) :3362-3369
[8]   Temperature in non-equilibrium states:: a review of open problems and current proposals [J].
Casas-Vázquez, J ;
Jou, D .
REPORTS ON PROGRESS IN PHYSICS, 2003, 66 (11) :1937-2023
[9]   DERIVATION OF OHM LAW IN A DETERMINISTIC MECHANICAL MODEL [J].
CHERNOV, NI ;
EYINK, GL ;
LEBOWITZ, JL ;
SINAI, YG .
PHYSICAL REVIEW LETTERS, 1993, 70 (15) :2209-2212
[10]   TRANSPORT-COEFFICIENTS AND LYAPUNOV EXPONENTS [J].
COHEN, EGD .
PHYSICA A, 1995, 213 (03) :293-314