scholarly journals An efficient algorithm of the unified stochastic particle Bhatnagar-Gross-Krook method for the simulation of multi-scale gas flows

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Fei Fei ◽  
Yang Ma ◽  
Jie Wu ◽  
Jun Zhang
Keyword(s):  
Direct Simulation Monte Carlo ◽  
Particle Method ◽  
Particle Methods ◽  
Gas Flows ◽  
Dsmc Method ◽  
Multi Scale ◽  
Virtual Particles ◽  
Spatial Reconstruction ◽  
Simulation Monte Carlo ◽  
Stochastic Particle

AbstractThe unified stochastic particle method based on the Bhatnagar-Gross-Krook model (USP-BGK) has been proposed recently to overcome the low accuracy and efficiency of the traditional stochastic particle methods, such as the direct simulation Monte Carlo (DSMC) method, for the simulation of multi-scale gas flows. However, running with extra virtual particles and space interpolation, the previous USP-BGK method cannot be directly transplanted into the existing DSMC codes. In this work, the implementation of USP-BGK is simplified using new temporal evolution and spatial reconstruction schemes. As a result, the present algorithm of the USP-BGK method is similar to the DSMC method and can be implemented efficiently based on any existing DSMC codes just by modifying the collision module.

scholarly journals An Efficient Algorithm of the Unified Stochastic Particle Bhatnagar-Gross-Krook Method for the Simulation of Multi-Scale Gas Flows

2021 ◽  
Author(s):  
Fei Fei ◽  
Yang Ma ◽  
Jie Wu ◽  
Jun Zhang
Keyword(s):  
Direct Simulation Monte Carlo ◽  
Particle Method ◽  
Particle Methods ◽  
Gas Flows ◽  
Dsmc Method ◽  
Multi Scale ◽  
Virtual Particles ◽  
Spatial Reconstruction ◽  
Simulation Monte Carlo ◽  
Stochastic Particle

Abstract The unified stochastic particle method based on the Bhatnagar-Gross-Krook model (USP-BGK) has been proposed recently to overcome the low accuracy and efficiency of the traditional stochastic particle methods, such as the direct simulation Monte Carlo (DSMC) method, for the simulation of multi-scale gas flows. However, running with extra virtual particles and space interpolation, the previous USP-BGK method cannot be directly transplanted into the existing DSMC codes. In this work, the implementation of USP-BGK is simplified using new temporal evolution and spatial reconstruction schemes. As a result, the present algorithm of the USP-BGK method is similar to the DSMC method and can be implemented efficiently based on any existing DSMC codes just by modifying the collision module.

Assessment of Impingement Effects in the Isentropic Core of a Small Satellite Control Thruster Plume

1989 ◽  
Vol 203 (2) ◽  
pp. 97-103 ◽  
Author(s):  
I D Boyd ◽  
J P W Stark
Keyword(s):  
Direct Simulation Monte Carlo ◽  
Particle Method ◽  
Accurate Estimation ◽  
Computational Techniques ◽  
Dsmc Method ◽  
Discrete Particle ◽  
Simulation Monte Carlo ◽  
Discrete Particle Method ◽  
Particle Approach ◽  
The Continuum

Two computational techniques commonly employed in the calculation of rocket and thruster expansion plumes are assessed. These are the method of characteristics (MOC), which is derived from the continuum Euler equations, and the direct simulation Monte Carlo (DSMC) method, which adopts a discrete particle approach. These techniques vary both in the computational expense and in the accuracy and detail of the solutions that they provide, depending upon the regime of application. The assessment is made with reference to the plume expanding from a small monopropellant hydrazine thruster and concentrates on the isentropic core of the jet for the flow regime lying between the continuum and free molecular limits. It is found that the more numerically intensive DSMC method offers the better correspondence to the available experimental data. In addition, large differences in typical impingement effects such as drag force and heat transfer are found at the free molecular limit of the plume expansion for the two predictive techniques. It is concluded that accurate estimation of impingement potential may only be achieved through application of the discrete particle method.

Numerical Methods for the Kinetic Theory of Fluids

2018 ◽  
Author(s):  
Sauro Succi
Keyword(s):  
Molecular Dynamics ◽  
Monte Carlo ◽  
Numerical Methods ◽  
Kinetic Theory ◽  
Computational Efficiency ◽  
Lattice Boltzmann ◽  
Direct Simulation Monte Carlo ◽  
Particle Methods ◽  
Direct Simulation ◽  
Simulation Monte Carlo

This chapter provides a bird’s eye view of the main numerical particle methods used in the kinetic theory of fluids, the main purpose being of locating Lattice Boltzmann in the broader context of computational kinetic theory. The leading numerical methods for dense and rarified fluids are Molecular Dynamics (MD) and Direct Simulation Monte Carlo (DSMC), respectively. These methods date of the mid 50s and 60s, respectively, and, ever since, they have undergone a series of impressive developments and refinements which have turned them in major tools of investigation, discovery and design. However, they are both very demanding on computational grounds, which motivates a ceaseless demand for new and improved variants aimed at enhancing their computational efficiency without losing physical fidelity and vice versa, enhance their physical fidelity without compromising computational viability.

Investigation of the Squeeze Film Dynamics Underneath a Microstructure With Large Oscillation Amplitudes and Inertia Effects

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Nadim A. Diab ◽  
Issam A. Lakkis
Keyword(s):  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Squeeze Film ◽  
Dsmc Method ◽  
Inertia Effects ◽  
Flow Parameters ◽  
Fluid Behavior ◽  
Dimensionless Groups ◽  
Simulation Monte Carlo ◽  
The Impact

This paper presents direct simulation Monte Carlo (DSMC) numerical investigation of the dynamic behavior of a gas film in a microbeam. The microbeam undergoes large amplitude harmonic motion between its equilibrium position and the fixed substrate underneath. Unlike previous work in literature, the beam undergoes large displacements throughout the film gap thickness and the behavior of the gas film along with its impact on the moving microstructure (force exerted by gas on the beam's front and back faces) is discussed. Since the gas film thickness is of the order of few microns (i.e., 0.01 < Kn < 1), the rarefied gas exists in the noncontinuum regime and, as such, the DSMC method is used to simulate the fluid behavior. The impact of the squeeze film on the beam is investigated over a range of frequencies and velocity amplitudes, corresponding to ranges of dimensionless flow parameters such as the Reynolds, Strouhal, and Mach numbers on the gas film behavior. Moreover, the behavior of compressibility pressure waves as a function of these dimensionless groups is discussed for different simulation case studies.

scholarly journals Development of an Efficient Particle Approach for Micro-Scale Gas Flow Simulations

2009 ◽  
Author(s):  
Quanhua Sun ◽  
Feng Li ◽  
Jing Fan ◽  
Chunpei Cai
Keyword(s):  
Cell Size ◽  
Gas Flow ◽  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Gas Flows ◽  
Dsmc Method ◽  
Low Speed ◽  
Micro Scale ◽  
Information Preservation ◽  
Cfd Method

The micro-scale gas flows are usually low-speed flows and exhibit rarefied gas effects. It is challenging to simulate these flows because traditional CFD method is unable to capture the rarefied gas effects and the direct simulation Monte Carlo (DSMC) method is very inefficient for low-speed flows. In this study we combine two techniques to improve the efficiency of the DSMC method. The information preservation technique is used to reduce the statistical noise and the cell-size relaxed technique is employed to increase the effective cell size. The new cell-size relaxed IP method is found capable of simulating micro-scale gas flows as shown by the 2D lid-driven cavity flows.

1D and 2D Monte Carlo Simulations of Pulsed Laser Ablation of Si/Ga Into Ar/O2 with a Substrate

1995 ◽  
Vol 389 ◽  
Author(s):  
D. L. Capewell ◽  
D. G. Goodwin
Keyword(s):  
Monte Carlo ◽  
Room Temperature ◽  
Particle Flux ◽  
Film Growth ◽  
Pulsed Laser ◽  
Direct Simulation Monte Carlo ◽  
Dsmc Method ◽  
Simulation Monte Carlo ◽  
Cylindrical Volume ◽  
Background Gas

ABSTRACTThe Direct Simulation Monte Carlo (DSMC) method is applied to the problem of pulsed laser deposition in both ID and 2D axisymmetric simulations. A source of target atoms expands into a cylindrical volume containing a background gas at room temperature and pressures up to 100 mTorr in the presence of a diffusely reflecting substrate. At regular intervals, the density and temperature of each species are computed. Particle flux and energy per particle incident on the substrate are also monitored as functions of time. The simulation results qualitatively compare, well with experimental plume diagnostics, with measured film growth rates as a function of background gas pressure, and with measured changes in film growth stoichiometry resulting from the introduction of a background gas into a two-component PLD system.

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