scholarly journals Variable slip coefficient in binary lattice Boltzmann models

Open Physics ◽  
2008 ◽  
Vol 6 (4) ◽  
Author(s):  
Lajos Szalmás
Keyword(s):  
Boundary Layer ◽  
Numerical Simulations ◽  
Lattice Boltzmann ◽  
Boundary Layer Theory ◽  
Knudsen Layer ◽  
Slip Coefficient ◽  
Boundary Slip ◽  
Gaseous Flows ◽  
Binary Lattice ◽  
Lattice Boltzmann Models

AbstractWe present a new method in order to obtain variable slip coefficient in binary lattice Boltzmann models to simulate gaseous flows. We present the Boundary layer theory. We study both the single-and multi-fluid BGK-type models as well. The boundary slip and the Knudsen layer are analyzed in detail. Benchmark simulations are carried out in order to compare the analytical derivation with the numerical results. Excellent agreement is found between the two analytical formalism and the numerical simulations.

LATTICE BOLTZMANN SIMULATION OF GASEOUS FINITE-KNUDSEN MICROFLOWS

2010 ◽  
Vol 21 (06) ◽  
pp. 769-783 ◽  
Author(s):  
ZHI-WEI TIAN ◽  
SHENG CHEN ◽  
CHU-GUANG ZHENG
Keyword(s):  
Lattice Boltzmann ◽  
Velocity Slip ◽  
Knudsen Layer ◽  
High Order ◽  
Correction Function ◽  
Transitional Regime ◽  
Lattice Boltzmann Simulation ◽  
Gaseous Flows ◽  
Boltzmann Method ◽  
Better Than

In this study, microscale gaseous flows in the transitional regime have been investigated by lattice Boltzmann method (LBM). In the existing microflows LBM models, the Knudsen layer correction function has been introduced into the models. According to the kinetic theory rigorously, we choose a proper expression of correction function, and then determine its adjustable parameter. A substitute high-order boundary conditions treatment is adopted to capture the velocity slip, without any difficulties in computing the high-order velocity derivatives. The numerical results of two typical microflows show that: the present results agree with the analytical solutions better than the existing LBM simulations. Evident improvements can also be found, especially for finite Kn microflows.

Fractional Propagation and the Elimination of Staggered Invariants in Lattice-BGK Models

1997 ◽  
Vol 08 (04) ◽  
pp. 753-761 ◽  
Author(s):  
Yue-Hong Qian
Keyword(s):  
Complex Systems ◽  
Numerical Simulations ◽  
Lattice Boltzmann ◽  
Large Scale ◽  
Lattice Gas ◽  
Dynamical Equations ◽  
Lattice Gas Models ◽  
Lattice Boltzmann Models

Lattice-based models have been attracting much interest in recent years and have been applied to many complex systems. The derivation of large scale dynamical equations of lattice-gas models as well as lattice-Boltzmann models was based on the belief that only the physically interesting quantities (mass, momentum and energy) are conserved. Staggered invariants in lattice-gas models were found in 1988 and there have been no efficient methods to eliminate these invariants. In this paper, we will first discuss the existence of staggered invariants, then we propose to use fractional propagation as an effective way of suppressing these undesired invariants. Numerical simulations will be used to confirm the theory and to show the improvement of computations.

scholarly journals Energy Conserving Lattice Boltzmann Models for Incompressible Flow Simulations

2013 ◽  
Vol 13 (3) ◽  
pp. 603-613 ◽  
Author(s):  
Shiwani Singh ◽  
Siddharth Krithivasan ◽  
Iliya V. Karlin ◽  
Sauro Succi ◽  
Santosh Ansumali
Keyword(s):  
Numerical Simulations ◽  
Incompressible Flow ◽  
Lattice Boltzmann ◽  
Cavity Flow ◽  
Flow Simulations ◽  
Flow Past ◽  
Energy Conserving ◽  
Isothermal Flows ◽  
Lattice Boltzmann Models ◽  
Flow Past A Sphere

AbstractIn this paper, we highlight the benefits resulting from imposing energy-conserving equilibria in entropic lattice Boltzmann models for isothermal flows. The advantages are documented through a series of numerical simulations, such as Taylor-Green vortices, cavity flow and flow past a sphere.

LATTICE BOLTZMANN METHOD WITH OPTIMIZED BOUNDARY LAYER AT FINITE KNUDSEN NUMBERS

2008 ◽  
Vol 19 (02) ◽  
pp. 249-257 ◽  
Author(s):  
LAJOS SZALMÁS
Keyword(s):  
Transition Region ◽  
Lattice Boltzmann ◽  
Continuous Solution ◽  
Optimization Procedure ◽  
Knudsen Layer ◽  
Lattice Boltzmann Models ◽  
Boltzmann Method ◽  
First Time ◽  
Fine Tune ◽  
Slip Coefficients

We present an optimization procedure in high-order lattice Boltzmann models in order to fine-tune the method for micro-channel flows in the transition region. Both the first and second slip coefficients are tunable, and the hydrodynamic and Knudsen layer solutions can be tailored. Very good results are obtained in comparison with the continuous solution for hard sphere molecules. For the first time, we provide an accurate description of Poiseuille flow in the transition region.

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