DIRECT SIMULATION MONTE CARLO FOR DENSE HARD SPHERES

2013 ◽  
Vol 25 (01) ◽  
pp. 1340023 ◽  
Author(s):  
LIU CHAO ◽  
SANG KYU KWAK ◽  
SANTOSH ANSUMALI
Keyword(s):  
Monte Carlo ◽  
Hard Sphere ◽  
Hard Spheres ◽  
Direct Simulation Monte Carlo ◽  
Direct Simulation ◽  
Enskog Theory ◽  
Dsmc Method ◽  
Dense System ◽  
Simulation Monte Carlo ◽  
Excellent Accuracy

We propose a modified direct simulation Monte Carlo (DSMC) method, which extends the validity of DSMC from rarefied to dense system of hard spheres (HSs). To assess this adapted method, transport properties of hard-sphere (HS) systems have been predicted both at dense states as well as dilute, and we observed the excellent accuracy over existing DSMC-based algorithms including the Enskog theory. The present approach provides an intuitive and systematic way to accelerate molecular dynamics (MD) via mesoscale approach.

Various Boundary Condition Implementation to Study Microfilters Using DSMC Simulation

2010 ◽  
Author(s):  
Masoud Darbandi ◽  
Hassan Akhlaghi ◽  
Abolfazl Karchani ◽  
Soheyl Vakili
Keyword(s):  
Boundary Condition ◽  
Monte Carlo ◽  
Gas Flow ◽  
Direct Simulation Monte Carlo ◽  
Direct Simulation ◽  
Dsmc Method ◽  
Uniform Distributions ◽  
Dsmc Simulation ◽  
Flow Through ◽  
Simulation Monte Carlo

In this study, we present a vast boundary condition treatment to simulate gas flow through microfilters using direct simulation Monte Carlo (DSMC) method. We examine the effects of different boundary condition treatments on the density, pressure, and velocity distributions and suggest the best conditions to simulate gas flow through microfilters. We also refine the effects of upstream and downstream locations on the solution. The results show that uniform distributions can be achieved if we apply the inlet/outlet boundary condition at appropriate upstream and downstream distances. We also show that all the suggested boundary conditions suitably predict the pressure drop coefficient factor across the filter. To evaluate the current results they are compared with some available empirical formulations.

Direct Simulation Monte Carlo Calculation: Strategies for Using Complex Initial Conditions

2002 ◽  
Vol 731 ◽  
Author(s):  
Michael I. Zeifman ◽  
Barbara J. Garrison ◽  
Leonid V. Zhigilei
Keyword(s):  
Monte Carlo ◽  
Laser Ablation ◽  
Cluster Size ◽  
Initial Conditions ◽  
Direct Simulation Monte Carlo ◽  
Statistical Processing ◽  
Condensed State ◽  
Direct Simulation ◽  
Dsmc Method ◽  
Simulation Monte Carlo

AbstractModeling of phenomena is increasingly being used to obtain an understanding of important physical events as well as to predict properties that can be directly tied to experimental data. For systems with relatively low densities of particles, the Direct Simulation Monte Carlo (DSMC) method is well suited for modeling gases with non-equilibrium distributions, coupled gas-dynamic and reaction effects, emission and absorption of radiation. On the other hand, if the density of particles is large such as in dense gases or condensed matter, the DSMC method is not appropriate and techniques such as molecular dynamics (MD) simulations are employed. There are phenomena such as laser ablation, however, in which the system evolves from a condensed state appropriate to be studied with MD to an expanding rarified gas appropriate to be studied with DSMC.The work presented here discusses the means of transferring information from a MD simulation of laser ablation to a DSMC simulation of the plume expansion. The presence of clusters in the MD output poses the main computational challenge. When the laser fluence is above the ablation threshold, the cluster size distribution is very broad (up to 10,'000's of particles per cluster) but there are relatively few of each cluster size. We have developed a method for statistical processing of the MD results and have represented the cluster size as a random variable. Various aspects of the coupling between the MD and DSMC models are discussed and several examples are presented.

DSMC Simulation of Ion Generation in Atmospheric Air

2003 ◽  
Author(s):  
W. Zhang ◽  
T. S. Fisher ◽  
D. J. Schilitz ◽  
S. V. Garimella
Keyword(s):  
Monte Carlo ◽  
Direct Simulation Monte Carlo ◽  
Direct Simulation ◽  
Dsmc Method ◽  
Atmospheric Air ◽  
Section Data ◽  
Ion Generation ◽  
The Monte Carlo Method ◽  
Dsmc Simulation ◽  
Simulation Monte Carlo

The generation of ions in air has several useful applications, such as electrohydrodynamic (EHD) pumping, air purification and isolation breakdown prevention. In this paper, ion generation processes in atmospheric air are simulated using a Direct Simulation Monte Carlo (DSMC) method. Details of the collision model are discussed. A C++ code is developed to implement the Monte Carlo method with cross-section data compiled from the literature. Self-sustaining discharge and ionization can be reproduced in the simulation under sufficient voltage bias, and the associated trends obtained are similar to those predicted by Paschen’s curve for a parallel-plate configuration.

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