A hybrid numerical scheme designed for hypersonic non-equilibrium flows is presented which solves the Navier-Stokes equations in regions of near-equilibrium and uses the direct simulation Monte Carlo method where the flow is in non-equilibrium. Detailed analysis of each stage of the hybrid cycle illustrates the difficulty in defining physically correct DSMC boundary conditions in regards to bot...

A modular particle-continuum (MPC) numerical method is used to simulate steady-state hypersonic flows which exhibit local regions of non-equilibrium embedded within mainly continuum flow fields. The MPC method loosely couples direct simulation Monte Carlo (DSMC) and Navier-Stokes (NS) methods which operate in different regions, use different mesh densities, and are updated using different sized...

In this study, the effect of rarefied region in rotor centrifuge was investigated. a centrifuge, feed inlet is positioned area. The continuum hypothesis not valid area; therefore, it desires to be analyzed by probabilistic methods like Direct Simulation Monte Carlo (DSMC). present Computational Fluid Dynamic (CFD) method used simulate area, and DSMC employed An implicit coupled density-based sc...

A hybrid particle scheme is presented for the simulation of compressible gas flows involving both continuum regions and rarefied regions with strong translational nonequilibrium. The direct simulation Monte Carlo (DSMC) method is applied in rarefied regions, while remaining portions of the flowfield are simulated using a DSMC-based low diffusion particle method for inviscid flow simulation. The...

A hybrid particle scheme, which is based on the direct simulation Monte Carlo (DSMC) method and incorporates a low diffusion particle method for continuum flow simulation, is extended for improved efficiency and wider applicability. The hybrid scheme is intended for simulation of gas flows involving a wide range of Knudsen number regimes, where strong coupling is desired between calculations in...

A new discrete velocity scheme for solving the Boltzmann equation is described. Directly solving the Boltzmann equation is computationally expensive because, in addition to working in physical space, the nonlinear collision integral must also be evaluated in a velocity space. Collisions between each point in velocity space with all other points in velocity space must be considered in order to c...

The Direct Simulation Monte Carlo (DSMC) method, developed originally to calculate rarefied gas dynamical problems, is applied to continuous flow including shocks assuming that the Knudsen number is sufficiently small. In particular, we study the formation of spiral shocks in the accretion disc of a close binary system. The method involves viscosity and thermal conduction automatically, and can...

This paper presents a model for predicting the parallel scalability of Direct Simulation Monte Carlo (DSMC) simulations of rareeed gas ow. The performance implications of diierent connection topologies are considered. The analysis is independent of the simulation architecture, gridding technique, collision model, and implementation technique. The model is validated and constants of the model de...