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A hybrid MD-DSMC coupling method to investigate flow characteristics of micro-devices

DSpace at IIT Bombay

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Title A hybrid MD-DSMC coupling method to investigate flow characteristics of micro-devices
 
Creator WATVISAVE, DS
PURANIK, BP
BHANDARKAR, UV
 
Subject MOLECULAR-DYNAMICS
GAS-FLOWS
SIMULATION
MICROCHANNEL
CONTINUUM
FLUID
Molecular dynamics
Direct simulation Monte Carlo
Hybrid methods
Gas-surface interactions
High Knudsen number flow
 
Description A new methodology is proposed to couple Molecular Dynamics (MD) and Direct Simulation Monte Carlo (DSMC) methods to simulate high Knudsen number (Kn) flows. For this purpose a two-dimensional hybrid MD-DSMC code is developed. In this method gas-surface interactions are modeled using MD, and gas-gas interactions are modeled using DSMC method. Two-way coupling between MD and DSMC is implemented by employing buffer zones for both MD and DSMC regions. Bootstrap sampling and energy minimization algorithms are employed for dynamic coupling of these two methods since MD utilizes real number of molecules during simulation whereas DSMC utilizes a lesser number of simulated molecules. The hybrid methodology combines the advantages of both methods; it has the capability of modeling the gas-surface interaction accurately considering the effect of the presence of neighboring real number of gas molecules, while in the bulk it utilizes DSMC with only the simulated number of molecules thus increasing the computational efficiency significantly compared to pure MD codes. As a result comparatively large domain sizes can be simulated with realistic behavior at the walls. The utility of the hybrid method is demonstrated by simulating high Kn flows through a micro-channel, micro-nozzle and micro-scale shock tube. The effect of partial accommodation of gas molecules with the wall is seen to be captured dynamically with this approach. (C) 2015 Elsevier Inc. All rights reserved.
 
Publisher ACADEMIC PRESS INC ELSEVIER SCIENCE
 
Date 2016-01-14T14:18:54Z
2016-01-14T14:18:54Z
2015
 
Type Article
 
Identifier JOURNAL OF COMPUTATIONAL PHYSICS, 302,603-617
0021-9991
1090-2716
http://dx.doi.org/10.1016/j.jcp.2015.09.012
http://dspace.library.iitb.ac.in/jspui/handle/100/17709
 
Language en