scholarly journals Application of DSMC method to astrophysical flows

2003 ◽  
Vol 208 ◽  
pp. 425-426
Author(s):  
Takuya Matsuda ◽  
Hiromi Mizutani ◽  
Henri. M. J. Boffin
Keyword(s):  
Thermal Conduction ◽  
Rarefied Gas ◽  
Turbulent Viscosity ◽  
Direct Simulation Monte Carlo ◽  
Close Binary System ◽  
Close Binary ◽  
Direct Simulation ◽  
Dsmc Method ◽  
Simulation Monte Carlo ◽  
Astrophysical Flows

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 thus simulate turbulent viscosity.

Statistical Modeling of Rarefied Gas Channel Flows

2009 ◽  
Author(s):  
Seckin Gokaltun ◽  
Michael C. Sukop ◽  
George S. Dulikravich
Keyword(s):  
Lattice Boltzmann ◽  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Direct Simulation ◽  
Channel Axis ◽  
Dsmc Method ◽  
Gas Channel ◽  
Simulation Monte Carlo ◽  
Boltzmann Method ◽  
Linear Pressure Distribution

Lattice Boltzmann method (LBM) and direct simulation Monte Carlo (DSMC) method are used for analysis of moderate Knudsen number phenomena. Simulation results are presented for pressure-driven isothermal rarefied channel flow at various pressure ratios. Analytical equations for non-linear pressure distribution and velocity profiles along the channel axis are used to verify the present LBM and DSMC results. We conclude that the LBM method can be used as an alternative model to DSMC simulations.

Modeling Squeeze Films in the Vicinity of High Inertia Oscillating Microstructures

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Nadim A. Diab ◽  
Issam Lakkis
Keyword(s):  
Gas Flow ◽  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Direct Simulation ◽  
Micro Structure ◽  
Dsmc Method ◽  
High Frequencies ◽  
Lubrication Equation ◽  
Simulation Monte Carlo ◽  
Stiffness And Damping

This work investigates the effect of various assumptions proposed by the classical Reynolds lubrication equation. In particular, a microplate oscillating at high frequencies (beyond cutoff) and high velocities leading to appreciable displacement within the film gap is studied. An analytical model is derived with special emphasis on the fluid's inertia effect on the fluid/solid interface. By implementing the direct simulation Monte Carlo (DSMC) method, a numerical method for modeling rarefied gas flow, the analytically based model is adjusted for the force exerted by the gas on the oscillating micro-structure to capture various significant effects related to the fluid's inertia, compressibility, stiffness, and damping.

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.

Direct Simulation Monte Carlo Method for the Simulation of Rarefied Gas Flow in Discrete Track Recording Head/Disk Interfaces

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Maik Duwensee ◽  
Frank E. Talke ◽  
Shoji Suzuki ◽  
Judy Lin ◽  
David Wachenschwanz
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Gas Flow ◽  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Direct Simulation ◽  
Rarefied Gas Flow ◽  
Recording Head ◽  
Discrete Track ◽  
Simulation Monte Carlo

The direct simulation Monte Carlo method is used to study rarefied gas flow between an inclined plane slider bearing and a nanochannel representing one groove in discrete track recording head/disk interfaces. The forces acting on the slider are determined as a function of slider pitch angle, disk velocity, groove pitch, width, and groove depth. It is found that the influence of manufacturing tolerances on slider forces is smaller for deep and wide grooves than for the case of shallow and narrow grooves.

scholarly journals Simulation of Rarefied Gas Flow in a Rectangular Enclosure

2019 ◽  
Author(s):  
Sumit Chamling Rai ◽  
Jayesh Sanwal ◽  
K Ram Chandra Murthy
Keyword(s):  
Gas Flow ◽  
Rarefied Gas ◽  
Direct Simulation Monte Carlo ◽  
Stochastic Modelling ◽  
Dsmc Method ◽  
Driven Cavity ◽  
Simulation Monte Carlo ◽  
Computationally Intensive ◽  
Velocity Pressure ◽  
Good Agreement

The present work investigates the effects of rarefaction on gas flow patterns in a lid-driven cavity using the simulation package dsmcFoam, on the OpenFOAM platform. Direct Simulation Monte Carlo (DSMC) method is a simulation technique which caters to the regime in between the computationally intensive molecular dynamics solvers, as well as the often inaccurate NS based solvers (applied to the rarefied gas simulations). It was proposed by G.A. Bird which employs the stochastic modelling of particle motion.Simulations are performed and results are verified for the flow of a rarefied gas Argon) for different lid velocities within the domain. The results are presented as streamlines, contours of velocity, pressure and temperature, along with velocities in X and Y directions. They have been found to be in good agreement with the previous experimental and numerical observations. Our simulations show that these eddies are much harder to observe in the rarefied domain, and cannot be observed upto velocities as high as 200m/s in a cavity with aspect ratio 1.

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