Explicit formulations of G13-based gas kinetic flux solver (G13-GKFS) for simulation of continuum and rarefied flows

The Knudsen paradox—the non-monotonous variation of mass-flow rate with the Knudsen number—is a unique and well-established signature of micro-channel rarefied flows. A particle which is not of insignificant size in relation to the duct geometry can significantly alter the flow behavior when introduced in such a system. In this work, we investigate the effects of a stationary particle on a micro-channel Poiseuille flow, from continuum to free-molecular conditions, using the direct simulation Monte-Carlo (DSMC) method. We establish a hydrodynamic basis for such an investigation by evaluating the flow around the particle and study the blockage effect on the Knudsen paradox. Our results show that with the presence of a particle this paradoxical behavior is altered. The effect is more significant as the particle becomes large and results from a shift towards relatively more ballistic molecular motion at shorter geometrical distances. The need to account for combinations of local and non-local transport effects in modeling reactive gas–solid flows in confined geometries at the nano-scale and in nanofabrication of model pore systems is discussed in relation to these results.

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A Lattice Boltzmann Method for relativistic rarefied flows in (2+1) dimensions

Journal of Computational Science ◽

10.1016/j.jocs.2021.101320 ◽

2021 ◽

Vol 51 ◽

pp. 101320

Author(s):

L. Bazzanini ◽

A. Gabbana ◽

D. Simeoni ◽

S. Succi ◽

R. Tripiccione

Keyword(s):

Lattice Boltzmann Method ◽

Lattice Boltzmann ◽

Rarefied Flows ◽

Boltzmann Method

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Computing Micro Synthetic Jet in Slip Regime With Moving Membrane

Microelectromechanical Systems ◽

10.1115/imece2002-33770 ◽

2002 ◽

Cited By ~ 6

Author(s):

A. Rustem Aslan ◽

Oktay Baysal ◽

Firat O. Edis

Keyword(s):

Moving Boundary ◽

Pressure Field ◽

Wall Slip ◽

Synthetic Jet ◽

Navier Stokes ◽

Rarefied Flows ◽

Flow Simulations ◽

Slip Regime ◽

Velocity Magnitude ◽

Primary Focus

A Navier-Stokes (NS) solver for moving and deforming meshes has been modified to investigate numerically the diaphragm-driven flow in and out of two synthetic jet cavity geometries. The piezoelectric-driven diaphragm of the cavity is modeled in a realistic manner as a moving boundary to accurately compute the flow inside the jet cavity. The primary focus of the present paper is to describe the effect of cavity geometry and the wall slip, resulting from the relatively larger Kn number flows associated with micro sized geometries, on the exit jet velocity magnitude. Compressible flow simulations are required for rarefied flows to accurately predict the pressure field. The present computations for the quiescent external flow condition reveal that cavity geometry and the wall slip has an increasing effect on the magnitude of the average jet exit velocity as well as vortex shedding from the orifice.

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DSMC method on aerodynamic heating and temperature characteristic of hypersonic rarefied flows

10.1117/12.2244469 ◽

2016 ◽

Author(s):

Jing Ma ◽

Xingdong Bao ◽

Hongxia Mao ◽

Yanbing Dong

Keyword(s):

Temperature Characteristic ◽

Aerodynamic Heating ◽

Dsmc Method ◽

Rarefied Flows

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Distribution of the components of the building mixture in the presence of secondary raw materials during rotary mixing

E3S Web of Conferences ◽

10.1051/e3sconf/202022001060 ◽

2020 ◽

Vol 220 ◽

pp. 01060

Author(s):

Anna Kapranova ◽

Daria Bahaeva ◽

Dmitry Stenko ◽

Alexander Vatagin ◽

Anton Lebedev ◽

...

Keyword(s):

Raw Materials ◽

Physical And Mechanical Properties ◽

Distribution Functions ◽

Stochastic Description ◽

Rarefied Flows ◽

Secondary Raw Materials ◽

Characteristic Angle ◽

Two Stages ◽

The Given ◽

Number Of Particles

The purpose of this study is a stochastic description of the distribution of solid dispersed components, including those from secondary raw materials, according to the characteristic angle of scattering ϴij when receiving a construction mixture at the first stage of operation of the rotary apparatus. Two stages of the formation of rarefied flows are assumed: when scattering particles of components by elastic blades of a rotating drum and when interacting with the baffle surface. Modeling method this is energy method of Klimontovich Yu.L. The analysis of the efficiency of the first stage (rotary mixing) is carried out based on the obtained distribution functions of the number of particles of bulk components over the scattering angle, taking into account their physical and mechanical properties and a variety of design and operating parameters of the apparatus. The bulk of the particles of the mixed components are scattered at the initial angles of rotation of the mixing drum, when the deformation of the elastic blades is most significant. This is accompanied by the characteristic first bursts of the obtained distribution curves (ϴij< 0.1 rad) for the number of particles of the tested bulk materials at the given ranges of parameters.

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