Finite-size effects in dissipative particle dynamics simulations

2006 ◽  
Vol 124 (8) ◽  
pp. 084104 ◽  
Author(s):  
María Eugenia Velázquez ◽  
Armando Gama-Goicochea ◽  
Minerva González-Melchor ◽  
Maricela Neria ◽  
José Alejandre
Keyword(s):  
Size Effects ◽  
Dissipative Particle Dynamics ◽  
Finite Size ◽  
Particle Dynamics ◽  
Finite Size Effects ◽  
Dynamics Simulations

Frictional Properties of Self-Assembled Alkylsilane Chains on Silica

2001 ◽  
Vol 687 ◽  
Author(s):  
M. Chandross ◽  
B. Park ◽  
M. Stevens ◽  
G.S. Grest
Keyword(s):  
Size Effects ◽  
Finite Size ◽  
Shear Velocity ◽  
Finite Size Effects ◽  
Silica Surfaces ◽  
Frictional Properties ◽  
Covalently Bonded ◽  
Comparable Effect ◽  
System Data ◽  
Dynamics Simulations

AbstractWe present the results of molecular dynamics simulations of pairs of alkylsilane monolayers on silica surfaces under shear. In particular, we investigate the effects of shear velocity on the friction for chains of 6, 8, 12, and 18 carbon atoms covalently bonded to a crystalline surface. Our studies are performed at loads close to 0.2 and 2 GPa for relative velocities of 0.2, 2.0, and 20.0 m/s. We find that for perfect (defect-free) monolayers, the effects of chain length and velocity are weak, indicating that the experimentally measured dependence of friction on these properties is primarily due to defects in the monolayer. We have investigated possible finite size effects by varying our system dimensions from 43 Å ×50 Å Å to 174 Å × 201 Å. We find that increasing the surface area by a factor of N reduces the noise in the shear stress by a factor of , and has a comparable effect to averaging the smaller system data over bins of points. This indicates that finite size effects are negligible in our simulations.

scholarly journals Lattice induced crystallization of nanodroplets: the role of finite-size effects and substrate properties in controlling polymorphism

Nanoscale ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 4921-4926 ◽  
Author(s):  
Julien Lam ◽  
James F. Lutsko
Keyword(s):  
Molecular Dynamics ◽  
Size Effects ◽  
Finite Size ◽  
Solid Substrate ◽  
General Phenomenon ◽  
Finite Size Effects ◽  
Substrate Properties ◽  
Dynamics Simulations ◽  
Induced Crystallization

Freezing a nanodroplet deposited on a solid substrate leads to the formation of crystalline structures. We study the inherent mechanisms underlying this general phenomenon by means of molecular dynamics simulations.

Resolution Effects in Dissipative Particle Dynamics Simulations

1998 ◽  
Vol 09 (08) ◽  
pp. 1307-1318 ◽  
Author(s):  
Edo S. Boek ◽  
Paul Van Der Schoot
Keyword(s):  
Dissipative Particle Dynamics ◽  
Finite Size ◽  
Coarse Graining ◽  
System Size ◽  
Particle Dynamics ◽  
Coarse Grained ◽  
Fluid Filtration ◽  
Colloidal Spheres ◽  
Effective Attraction ◽  
Dynamics Simulations

Dissipative Particle Dynamics (DPD) simulations were performed to investigate resolution or "coarse graining" effects on the simulation results. Fluid flow through a periodic array of spheres has been studied as a model for fluid filtration into a porous medium. In our model system, it appears that quantitatively correct results for the dimensionless drag can be obtained for relatively small system sizes. For higher solid volume fractions, it is necessary to increase the system size to avoid finite size and resolution effects. Simulations of colloidal spheres suspended in a DPD fluid show effective attraction between the large colloid particles, causing depletion aggregation. This effect may be expected as a consequence of the coarse-grained nature of the DPD fluid. By imposing a steady shear rate the aggregation can be suppressed. The results show that for dilute suspensions, the Brownian noise in the particle interactions causes an effective colloid polydispersity, which suppresses aggregation effects.

scholarly journals Patterns and Long Range Correlations in Idealized Granular Flows

1997 ◽  
Vol 08 (04) ◽  
pp. 953-965 ◽  
Author(s):  
J. A. G. Orza ◽  
R. Brito ◽  
T. P. C. van Noije ◽  
M. H. Ernst
Keyword(s):  
Long Range ◽  
Size Effects ◽  
Hard Spheres ◽  
Finite Size ◽  
System Size ◽  
Spatial Correlations ◽  
Finite Size Effects ◽  
Long Range Correlations ◽  
Intrinsic Length ◽  
Dynamics Simulations

An initially homogeneous freely evolving fluid of inelastic hard spheres develops inhomogeneities in the flow field u(r, t) (vortices) and in the density field n (r, t)(clusters), driven by unstable fluctuations, δa = {δn, δu}. Their spatial correlations, <δa(r, t)δa(r′,t)>, as measured in molecular dynamics simulations, exhibit long range correlations; the mean vortex diameter grows as [Formula: see text]; there occur transitions to macroscopic shearing states, etc. The Cahn–Hilliard theory of spinodal decomposition offers a qualitative understanding and quantitative estimates of the observed phenomena. When intrinsic length scales are of the order of the system size, effects of physical boundaries and periodic boundaries (finite size effects in simulations) are important.

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