Parallel Fokker–Planck-DSMC algorithm for rarefied gas flow simulation in complex domains at all Knudsen numbers

In this work, we present a hybrid algorithm based on the Fokker-Planck (FP) kinetic model and direct simulation Monte Carlo (DSMC) for studies of rarefied gas flows. A particle based FP solution algorithm for rarefied gas flow simulations has recently been devised by the authors. The motivation behind the FP approximation is purely computational, i.e. due to the fact that the resulting random processes are continuous in time the computational cost of the corresponding time integration becomes independent of the Knudsen number. However, the method faces limitations for flows with very high Knudsen numbers (larger than approximately 5). In the method presented here, the FP approach is coupled with DSMC in order to gain from the efficiency of the FP model and from the accuracy of DSMC at small and large cell based Knudsen numbers, respectively.

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Information Preservation method application in low speed rarefied gas flow simulation

Proceedings of the 2016 5th International Conference on Advanced Materials and Computer Science ◽

10.2991/icamcs-16.2016.155 ◽

2016 ◽

Author(s):

Bokang Yan

Keyword(s):

Gas Flow ◽

Rarefied Gas ◽

Flow Simulation ◽

Rarefied Gas Flow ◽

Low Speed ◽

Information Preservation ◽

Preservation Method

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Adaptive particle–cell algorithm for Fokker–Planck based rarefied gas flow simulations

Computer Physics Communications ◽

10.1016/j.cpc.2016.11.003 ◽

2017 ◽

Vol 213 ◽

pp. 1-8 ◽

Cited By ~ 16

Author(s):

M. Pfeiffer ◽

M.H. Gorji

Keyword(s):

Gas Flow ◽

Rarefied Gas ◽

Rarefied Gas Flow ◽

Flow Simulations ◽

Fokker Planck

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New temperature jump boundary condition in high-speed rarefied gas flow simulations

Vietnam Journal of Mechanics ◽

10.15625/0866-7136/8760 ◽

2017 ◽

Vol 39 (2) ◽

pp. 165-176

Author(s):

Nam Tuan Phuong Le ◽

Ngoc Anh Vu ◽

Le Tan Loc ◽

Tran Ngoc Thoai

Keyword(s):

High Speed ◽

Gas Flow ◽

Sliding Friction ◽

Temperature Jump ◽

Stokes Equations ◽

Rarefied Gas ◽

Jump Condition ◽

Rarefied Gas Flow ◽

Flow Simulations ◽

Knudsen Numbers

The effect of the sliding friction has been important in calculating the heat flux of gas flow from the surface since there is some slip over the surface. There has not been any the temperature jump condition including the sliding friction part so far. In this paper, we will propose a new temperature jump condition that includes the sliding friction. Our new temperature jump condition will be evaluated for NACA0012 micro-airfoil in high-speed rarefied gas flow simulations using the CFD method, which solves the Navier-Stokes equations within the OpenFOAM framework with working gas as air. The airfoil case is simulated with various Knudsen numbers from 0.026 to 0.26, and the angles-of-attack (AOAs) from 0-deg to 20-deg. The surface gas temperatures predicting by our new temperature jump condition give good agreements with the DSMC data, especially the NACA0012 micro-airfoil cases with the high Knudsen numbers, Kn = 0.1, and Kn = 0.26 with AOA = 20-deg. for the lower surface.

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Numerical study of gas-surface interaction models for micro scale rarefied gas flow simulation

10.14711/thesis-b1514593 ◽

2015 ◽

Author(s):

Tengfei Liang

Keyword(s):

Gas Flow ◽

Rarefied Gas ◽

Numerical Study ◽

Flow Simulation ◽

Surface Interaction ◽

Rarefied Gas Flow ◽

Interaction Models ◽

Micro Scale

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Cubic Fokker-Planck-DSMC hybrid method for diatomic rarefied gas flow through a slit and an orifice

Vacuum ◽

10.1016/j.vacuum.2018.10.028 ◽

2019 ◽

Vol 159 ◽

pp. 125-133 ◽

Cited By ~ 5

Author(s):

Eunji Jun

Keyword(s):

Hybrid Method ◽

Gas Flow ◽

Rarefied Gas ◽

Rarefied Gas Flow ◽

Flow Through ◽

Fokker Planck

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Measurement of negative thermophoretic force

Journal of Fluid Mechanics ◽

10.1017/jfm.2016.464 ◽

2016 ◽

Vol 805 ◽

pp. 207-221 ◽

Cited By ~ 16

Author(s):

Ryan W. Bosworth ◽

A. L. Ventura ◽

A. D. Ketsdever ◽

S. F. Gimelshein

Keyword(s):

Spherical Particle ◽

Atmospheric Pressure ◽

Gas Flow ◽

Rarefied Gas ◽

Force Production ◽

Heated Wall ◽

Rarefied Gas Flow ◽

Thermophoretic Force ◽

Knudsen Numbers ◽

Close Proximity

The rarefied gas flow phenomenon of thermophoresis is studied experimentally on a macroscopic spherical particle with a diameter of 5.1 cm for pressures ranging from 0.01 to 10 Pa (Knudsen numbers $Kn$ from 10 to 0.01, respectively). Size scaling with matching Knudsen numbers makes the results applicable to microscale particles such as aerosol droplets at atmospheric pressure. Two sets of measurements are presented. The first set, complemented by numerical modelling based on the solution of the ellipsoidal statistical Bhatnagar–Gross–Krook kinetic equation, is focused on a spherical particle of high thermal conductivity in close proximity to a heated wall. The second set is conducted for the same particle placed in a linear thermal gradient established between two parallel walls. Results show the first reproducible measurements of negative thermophoretic force acting on a spherical particle in the direction from cold to hot, with values of the order of 5 % of the maximum hot to cold force production.

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