scholarly journals Comparative study of the discrete velocity and the moment method for rarefied gas flows

2019 ◽  
Author(s):  
Weiqi Yang ◽  
Xiao-Jun Gu ◽  
David. Emerson ◽  
Yonghao Zhang ◽  
Shuo Tang
Keyword(s):  
Comparative Study ◽  
Moment Method ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Discrete Velocity ◽  
Rarefied Gas Flows ◽  
The Moment

scholarly journals A comparative study of discrete velocity methods for low-speed rarefied gas flows

2018 ◽  
Vol 161 ◽  
pp. 33-46 ◽  
Author(s):  
Peng Wang ◽  
Minh Tuan Ho ◽  
Lei Wu ◽  
Zhaoli Guo ◽  
Yonghao Zhang
Keyword(s):  
Comparative Study ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Low Speed ◽  
Discrete Velocity ◽  
Rarefied Gas Flows

scholarly journals Analysis of the Moment Method and the Discrete Velocity Method in Modeling Non-Equilibrium Rarefied Gas Flows: A Comparative Study

2019 ◽  
Vol 9 (13) ◽  
pp. 2733
Author(s):  
Weiqi Yang ◽  
Shuo Tang ◽  
Hui Yang
Keyword(s):  
Moment Method ◽  
Rarefied Gas ◽  
Hermite Polynomials ◽  
Distribution Functions ◽  
Gas Flows ◽  
Thermally Induced ◽  
Rarefied Gas Flows ◽  
Discrete Velocity Method ◽  
The Moment ◽  
Non Equilibrium

In the present study, the performance of the moment method, in terms of accuracy and computational efficiency, was evaluated at both the macro- and microscopic levels. Three different types of non-equilibrium gas flows, including the force-driven Poiseuille flow, lid-driven and thermally induced cavity flows, were simulated in the slip and transition regimes. Choosing the flow fields obtained from the Boltzmann model equation as the benchmark, the accuracy and validation of Navier–Stokes–Fourier (NSF), regularized 13 (R13) and regularized 26 (R26) equations were explored at the macroscopic level. Meanwhile, we reconstructed the velocity distribution functions (VDFs) using the Hermite polynomials with different-order of molecular velocity moments, and compared them with the Boltzmann solutions at the microscopic level. Moreover, we developed a kinetic criterion to indirectly assess the errors of the reconstructed VDFs. The results have shown that the R13 and R26 moment methods can be faithfully used for non-equilibrium rarefied gas flows in the slip and transition regimes. However, as indicated from the thermally induced case, all of the reconstructed VDFs are still very close to the equilibrium state, and none of them can reproduce the accurate VDF profile when the Knudsen number is above 0.5.

scholarly journals A comparative study of the DSBGK and DVM methods for low-speed rarefied gas flows

2019 ◽  
Vol 181 ◽  
pp. 143-159 ◽  
Author(s):  
Minh Tuan Ho ◽  
Jun Li ◽  
Lei Wu ◽  
Jason M. Reese ◽  
Yonghao Zhang
Keyword(s):  
Comparative Study ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Low Speed ◽  
Rarefied Gas Flows

A hybrid approach to couple the discrete velocity method and Method of Moments for rarefied gas flows

2020 ◽  
Vol 410 ◽  
pp. 109397 ◽  
Author(s):  
Weiqi Yang ◽  
Xiao-Jun Gu ◽  
Lei Wu ◽  
David R. Emerson ◽  
Yonghao Zhang ◽  
...  
Keyword(s):  
Method Of Moments ◽  
Rarefied Gas ◽  
Hybrid Approach ◽  
Gas Flows ◽  
Discrete Velocity ◽  
Rarefied Gas Flows ◽  
Discrete Velocity Method

scholarly journals The Half-Range Moment Method in Harmonically Oscillating Rarefied Gas Flows

Fluids ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 17
Author(s):  
Giorgos Tatsios ◽  
Alexandros Tsimpoukis ◽  
Dimitris Valougeorgis
Keyword(s):  
Boundary Conditions ◽  
Stokes Flow ◽  
Moment Method ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Moment Equations ◽  
Rarefied Gas Flows ◽  
Flow Parameters ◽  
Discrete Velocity Method ◽  
Wide Range

The formulation of the half-range moment method (HRMM), well defined in steady rarefied gas flows, is extended to linear oscillatory rarefied gas flows, driven by oscillating boundaries. The oscillatory Stokes (also known as Stokes second problem) and the oscillatory Couette flows, as representative ones for harmonically oscillating half-space and finite-medium flow setups respectively, are solved. The moment equations are derived from the linearized time-dependent BGK kinetic equation, operating accordingly over the positive and negative halves of the molecular velocity space. Moreover, the boundary conditions of the “positive” and “negative” moment equations are accordingly constructed from the half-range moments of the boundary conditions of the outgoing distribution function, assuming purely diffuse reflection. The oscillatory Stokes flow is characterized by the oscillation parameter, while the oscillatory Couette flow by the oscillation and rarefaction parameters. HRMM results for the amplitude and phase of the velocity and shear stress in a wide range of the flow parameters are presented and compared with corresponding results, obtained by the discrete velocity method (DVM). In the oscillatory Stokes flow the so-called penetration depth is also computed. When the oscillation frequency is lower than the collision frequency excellent agreement is observed, while when it is about the same or larger some differences are present. Overall, it is demonstrated that the HRMM can be applied to linear oscillatory rarefied gas flows, providing accurate results in a very wide range of the involved flow parameters. Since the computational effort is negligible, it is worthwhile to consider the efficient implementation of the HRMM to stationary and transient multidimensional rarefied gas flows.

Comparative study of various approaches for modeling transitional hypersonic rarefied gas flows over blunt bodies

2012 ◽  
Author(s):  
I. G. Brykina ◽  
B. V. Rogov ◽  
G. A. Tirskiy ◽  
V. A. Titarev ◽  
S. V. Utyuzhnikov
Keyword(s):  
Comparative Study ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Rarefied Gas Flows ◽  
Blunt Bodies

Comparative study between computational and experimental results for binary rarefied gas flows through long microchannels

2010 ◽  
Vol 9 (6) ◽  
pp. 1103-1114 ◽  
Author(s):  
Lajos Szalmas ◽  
Jeerasak Pitakarnnop ◽  
Sandrine Geoffroy ◽  
Stephane Colin ◽  
Dimitris Valougeorgis
Keyword(s):  
Comparative Study ◽  
Rarefied Gas ◽  
Experimental Results ◽  
Gas Flows ◽  
Rarefied Gas Flows

Shock polar investigation in supersonic rarefied gas flows over a circular cylinder

2021 ◽  
Vol 33 (5) ◽  
pp. 052006
Author(s):  
Hassan Akhlaghi ◽  
Ehsan Roohi ◽  
Abbas Daliri ◽  
Mohammad-Reza Soltani
Keyword(s):  
Circular Cylinder ◽  
Rarefied Gas ◽  
Gas Flows ◽  
Rarefied Gas Flows
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