@Article{AAMM-2-609,
author = {Suga , KazuhikoTakenaka , SusumuIto , Takahiko and Kaneda , Masayuki},
title = {Lattice Boltzmann Flow Simulation in a Combined Nanochannel},
journal = {Advances in Applied Mathematics and Mechanics},
year = {2010},
volume = {2},
number = {5},
pages = {609--625},
abstract = {<p style="text-align: justify;">The widely used micro-flow wall-boundary conditions for lattice
Boltzmann method (LBM) are evaluated in a force driven combined
nanochannel flow. The flow field consists of a two-dimensional
nanochannel (mother channel) of an infinite length having flat
plates of a finite length inside. The flat plate is set above the
bottom wall of the nanochannel with a narrow gap. The flow, thus,
develops through this narrow gap (narrower channel) and the other
side of the plate (wide gap). The Knudsen number based on the mother
channel height is Kn=0.14 whereas the characteristic Knudsen
number in the narrower channel is 1.1. To obtain the reference
data, the molecular dynamics (MD) simulation is performed with a
fully diffusive wall condition. The LBMs are based on the lattice
BGK model and with the bounce-back/specular reflection (BSBC) and
the diffuse scattering (DSBC) wall boundary conditions. The
relaxation time is modified to include sensitivity to Kn. The DSBC
shows generally satisfactory results in the test flow cases
including fully developed force driven Poiseuille flows, where the
BSBC performs worse at Kn&gt;0.5 with a fixed bridge coefficient of $b=0.7$. This results in its overprediction of the flow rate in
the narrower channel region since the characteristic Knudsen number
there is 1.1. The MD simulation suggests that the flow develops
gradually through the narrower channel region though all the LBM
predictions show almost instant flow development. This fact suggests
that the relaxation time model needs to have more sensitivity to the
locally defined Kn. Further discussions of the BSBC with a different
set of models suggest that the regularization process is required
for predicting complex nanoscale flows.</p>},
issn = {2075-1354},
doi = {https://doi.org/10.4208/aamm.10-10S06},
url = {http://global-sci.org/intro/article_detail/aamm/8350.html}
}