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...

A grid-free variant of the Direct Simulation Monte Carlo (DSMC) method is proposed, named the Isotropic DSMC (I-DSMC) method, that is suitable for simulating dense fluid flows at molecular scales. The I-DSMC algorithm eliminates all grid artifacts from the traditional DSMC algorithm; it is Galilean invariant and microscopically isotropic. The stochastic collision rules in I-DSMC are modified to...

We perform a numerical study of the fluctuations of the rescaled hydrodynamic transverse velocity field during the cooling state of a homogeneous granular gas. We are interested in the role of Molecular Chaos for the amplitude of the hydrodynamic noise and its relaxation in time. For this purpose we compare the results of Molecular Dynamics (MD, deterministic dynamics) with those from Direct Si...

State-resolved analyses of N+N2 are performed using the direct simulation Monte Carlo (DSMC) method. In describing the elastic collisions in a state-resolved method, a statespecific total cross section is proposed. The state-resolved model is constructed from the state-specific total cross section and the state-to-state transition cross sections for boundbound and bound-free transitions taken f...

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...

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...

In this study computations of the two-dimensional Direct Simulation Monte Carlo (DSMC) method using Graphics Processing Units (GPUs) are presented. An all-device (GPU) computational approach is adopted – where the entire computation is performed on the GPU device, leaving the CPU idle which includes particle moving, indexing, collisions between particles and state sampling. The subsequent appli...