Hypersonic aerothermodynamics for a probe entering a planetary atmosphere is an important issue in space exploration. The probe experiences various Knudsen number regimes, ranging from rarefied to continuum, due to density variation in the planet’s atmosphere. To simulate such multiscale flows, a novel hybrid particle scheme is employed in the present work. The hybrid particle scheme employs th...

A multiscale method that couples direct simulation Monte Carlo (DSMC) method with Navier-Stokes equations is presented. The multiscale method is based on the Schwarz coupling of the DSMC and Navier-Stokes subdomains. Dirichlet boundary conditions are used at the coupling interfaces. The Navier-Stokes equations are solved using a scattered point based finite cloud method. Data interpolation betw...

The direct simulation Monte Carlo (DSMC) method is one of the most popular numerical methods used to model rarefied gas environment flows. In order to predict the accuracy of a solution obtained by the DSMC method we have to be able to estimate its accuracy. In the work presented here we have developed a technique to estimate the numerical accuracy of the DSMC method. This paper presents a deri...

This study examines a new hybrid particle scheme used as an alternative means of multiscale flow simulation. The hybrid particle scheme employs the direct simulation Monte Carlo (DSMC) method in rarefied flow regions and the low diffusion (LD) particle method in continuum flow regions. The numerical procedures of the low diffusion particle method are implemented within an existing DSMC algorith...

A low diffusion particle method for simulating compressible low Knudsen number gas flows is modified for application to flows involving nonequilibrium distributions in rotational and vibrational energy modes. This method is closely based on the direct simulation Monte Carlo (DSMC) method, and has been developed for use in a strongly coupled hybrid scheme with DSMC. In simulations employing this...

The implementation of a modular particle-continuum (MPC) numerical method is presented which solves the Navier-Stokes (NS) equations in regions of near-equilibrium and uses the direct simulation Monte Carlo (DSMC) method where the flow is in non-equilibrium. A mesh refinement procedure is described which allows the NS equations to be solved on a relatively coarse mesh using large implicit time-...

Gas flows encountered in micro/nano scale devices are often low speed and non-continuum. The Direct Simulation Monte Carlo (DSMC), a popular molecular based simulation technique for rarefied gas, has proven to be inefficient in dealing with low-speed gas flows. In this paper, we present the Octant Flux Splitting Information Preserving DSMC (OSIP-DSMC) method as an efficient DSMC method for micr...

Abstract. Pumping performance of a disk-type drag pump is studied numerically and experimentally. Molecular transition and slip flows that arise in a spiral channel on the rotating disk are simulated by using particle and continuum methods. The particle approach employs the direct simulation Monte Carlo (DSMC) method, and the continuum approach solves the Navier-Stokes (N-S) equations. A new DS...

A modular particle-continuum (MPC) numerical method is presented which solves the Navier-Stokes (NS) equations in regions of near-equilibrium and uses the direct simulation Monte Carlo (DSMC) method where the flow is in non-equilibrium. The MPC method is designed specifically for steady-state, hypersonic, nonequilibrium flows and couples existing, state-of-the-art DSMC and NS solvers into a sin...

This paper describes initial research into the development of an eeective parallel implementation of the direct simulation Monte Carlo (DSMC) method. DSMC is a widely established particle simulation method for the computation of rareeed gas ows, and in many cases is the only eeective means of ow prediction. The method is however computationally expensive in terms of time and memory usage, and f...