A high-order moment approach for capturing non-equilibrium phenomena in the transition regime

The method of moments is employed to extend the validity of continuum-hydrodynamic models into the transition-flow regime. An evaluation of the regularized 13 moment equations for two confined flow problems, planar Couette and Poiseuille flows, indicates some important limitations. For planar Couett...

Celý popis

Uložené v:
Podrobná bibliografia
Vydané v:Journal of fluid mechanics Ročník 636; s. 177 - 216
Hlavní autori: GU, XIAO-JUN, EMERSON, DAVID R.
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: Cambridge, UK Cambridge University Press 10.10.2009
Predmet:
Computational methods in fluid dynamics
Exact sciences and technology
Flow rates
Fluid dynamics
Fundamental areas of phenomenology (including applications)
Mathematics
Monte Carlo simulation
Physics
Rarefied gas dynamics
Theory
Velocity
Knudsen layer
Rarefied gas flow
Transition conditions
Poiseuille flow
Moments method
Digital simulation
Boundary conditions
Couette flow
Modelling
Velocity distribution
Argon
ISSN:0022-1120, 1469-7645
On-line prístup:Získať plný text
Tagy: Pridať tag
Žiadne tagy, Buďte prvý, kto otaguje tento záznam!
Popis
Shrnutí:The method of moments is employed to extend the validity of continuum-hydrodynamic models into the transition-flow regime. An evaluation of the regularized 13 moment equations for two confined flow problems, planar Couette and Poiseuille flows, indicates some important limitations. For planar Couette flow at a Knudsen number of 0.25, they fail to reproduce the Knudsen-layer velocity profile observed using a direct simulation Monte Carlo approach, and the higher-order moments are not captured particularly well. Moreover, for Poiseuille flow, this system of equations creates a large slip velocity leading to significant overprediction of the mass flow rate for Knudsen numbers above 0.4. To overcome some of these difficulties, the theory of regularized moment equations is extended to 26 moment equations. This new set of equations highlights the importance of both gradient and non-gradient transport mechanisms and is shown to overcome many of the limitations observed in the regularized 13 moment equations. In particular, for planar Couette flow, they can successfully capture the observed Knudsen-layer velocity profile well into the transition regime. Moreover, this new set of equations can correctly predict the Knudsen layer, the velocity profile and the mass flow rate of pressure-driven Poiseuille flow for Knudsen numbers up to 1.0 and captures the bimodal temperature profile in force-driven Poiseuille flow. Above this value, the 26 moment equations are not able to accurately capture the velocity profile in the centre of the channel. However, they are able to capture the basic trends and successfully predict a Knudsen minimum at the correct value of the Knudsen number.
Bibliografia:PII:S002211200900768X
ArticleID:00768
istex:E2226F5F5EC57D8A799F844A5A2992640EA8D933
ark:/67375/6GQ-4PS87R9J-2
SourceType-Scholarly Journals-1
ObjectType-Feature-1
content type line 14
ObjectType-Article-2
content type line 23
ISSN:0022-1120
1469-7645
DOI:10.1017/S002211200900768X