# Direct Simulation Monte Carlo Module

DSMCM is a two-dimensional DSMC(Direct Simulation Monte Carlo) software. DSMCM(Direct Simulation Monte Carlo Module) computes spatial distribution of density, temperature and pressure of each neutral species by particle model, DSMC method and test particle Monte Carlo method. Also The viscous flow field to free molecule flow field would be computed by new collision method.

## Description

DSMCM is based on DSMC(Direct Simulation Monte Carlo) method which is a probabilistic method to solve Boltzmann equation in gas theory. DSMCM is a module to compute the flow field of rarefied gas in various vacuum chambers. This module is applied to from viscous flow field to free molecule flow field by using the new collision method(U-system)[1][2]. The new collision method has been implemented to DSMCM. There are no restriction of mesh width depending on mean free path length by using this method. And test particle Monte Carlo method is used to compute rapidly the flow field of gas of which neutral density such as radicals or sputtered particles is very low compared with fed gas.

[1] Usami, M. and Nakayama T., Intermolecular Collision Scheme of DSMC Taking Molecular Locations within a Cell into Account, Rarefied Gas Dynamics, AIP Conference Proceedings, Vol.663 (2003), pp.374-381.

[2] Usami, M. and Mizuguchi, K., DSMC Calculation of Vortex Shedding behind a Flat Plate with a New Intermolecular Collision Scheme, Rarefied Gas Dynamics, AIP Conference Proceedings, Vol.762 (2005), pp.686-691.

## Input data

- Specify computational domain, flow-in, flow-out and obstacles defined by two-dimen sional rectangular mesh system in Cartesian or cylindrical (axial symmetry model) coordinates.
- Specify the following boundary conditions for flow-in for each species.
- Distribution of flow-in velocity
- Distribution of mass flux
- Distribution of temperature

## Output data

- Spatial distributions of density, pressure, temperature and flow-velocity for each species.
- Particle and energy fluxes of each species on the targets and walls.