NUMERICAL SIMULATION OF ISOTHERMAL MICRO FLOWS BY LATTICE BOLTZMANN METHOD AND THEORETICAL ANALYSIS OF THE DIFFUSE SCATTERING BOUNDARY CONDITION

2005 ◽  
Vol 16 (12) ◽  
pp. 1927-1941 ◽  
Author(s):  
X. D. NIU ◽  
C. SHU ◽  
Y. T. CHEW
Keyword(s):  
Boundary Condition ◽  
Theoretical Analysis ◽  
Lattice Boltzmann ◽  
Diffuse Scattering ◽  
Lattice Boltzmann Model ◽  
Numerical Validation ◽  
Micro Flows ◽  
Boltzmann Method ◽  
Boltzmann Model ◽  
Gas Bearing

A Lattice Boltzmann model for simulating micro flows has been proposed by us recently (Europhysics Letters, 67(4), 600–606 (2004)). In this paper, we will present a further theoretical and numerical validation of the model. In this regards, a theoretical analysis of the diffuse-scattering boundary condition for a simple flow is carried out and the result is consistent with the conventional slip velocity boundary condition. Numerical validation is highlighted by simulating the two-dimensional isothermal pressure-driven micro-channel flows and the thin-film gas bearing lubrication problems, and comparing the simulation results with available experimental data and analytical predictions.

Modeling of collapsing cavitation bubble near solid wall by 3D pseudopotential multi-relaxation-time lattice Boltzmann method

2017 ◽  
Vol 232 (3) ◽  
pp. 445-456 ◽  
Author(s):  
Minglei Shan ◽  
Yu Yang ◽  
Hao Peng ◽  
Qingbang Han ◽  
Changping Zhu
Keyword(s):  
Relaxation Time ◽  
Lattice Boltzmann ◽  
Cavitation Bubble ◽  
Solid Wall ◽  
Three Dimensional ◽  
Lattice Boltzmann Model ◽  
Bubble Collapse ◽  
Lattice Boltzmann Simulation ◽  
Boltzmann Method ◽  
Boltzmann Model

Understanding the dynamic characteristic of the cavitation bubble near a solid wall is a fundamental issue for the bubble collapse application and prevention. In the present work, an improved three-dimensional multi-relaxation-time pseudopotential lattice Boltzmann model is adopted to investigate the cavitation bubble collapse near the solid wall. With respect to thermodynamic consistency, Laplace law verification, the three-dimensional pseudopotential multi-relaxation-time lattice Boltzmann model is investigated. By the theoretical analysis, it is proved that the model can be regarded as a solver of the Rayleigh–Plesset equation, and confirmed by comparing the results of the lattice Boltzmann simulation and the Rayleigh–Plesset equation calculation for the case of cavitation bubble collapse in the infinite medium field. The bubble collapse near the solid wall is modeled using the improved pseudopotential multi-relaxation-time lattice Boltzmann model. We find the lattice Boltzmann simulation and the experimental results have the same dynamic process by comparing the bubble profiles evolution. Form the pressure field and the velocity field evolution it is found that the tapered higher pressure region formed near the top of the bubble is a crucial driving force inducing the bubble collapse. This exploratory research demonstrates that the lattice Boltzmann method is an alternative tool for the study of the interaction between collapsing cavitation bubble and matter.

scholarly journals Simulation of Thermomagnetic Convection in a Cavity Using the Lattice Boltzmann Model

2011 ◽  
Vol 2011 ◽  
pp. 1-14 ◽  
Author(s):  
Mahshid Hadavand ◽  
Antonio C. M. Sousa
Keyword(s):  
Natural Convection ◽  
Lattice Boltzmann ◽  
Magnetic Force ◽  
Electrical Current ◽  
Lattice Boltzmann Model ◽  
Thermomagnetic Convection ◽  
Microelectronic Devices ◽  
Third Dimension ◽  
Boltzmann Method ◽  
Boltzmann Model

Thermomagnetic convection in a differentially heated square cavity with an infinitely long third dimension is numerically simulated using the single relaxation time lattice Boltzmann method (LBM). This problem is of considerable interest when dealing with cooling of microelectronic devices, in situations where natural convection does not meet the cooling requirements, and forced convection is not viable due to the difficulties associated with pumping a ferrofluid. Therefore, circulation is achieved by imposing a magnetic field, which is created and controlled by placing a dipole at the bottom of the enclosure. The magnitude of the magnetic force is controlled by changing the electrical current through the dipole. In this study, the effects of combined natural convection and magnetic convection, which is commonly known as “thermomagnetic convection,” are analysed in terms of the flow modes and heat transfer characteristics of a magnetic fluid.

DEVELOPING LBM-BASED FLUX SOLVER AND ITS APPLICATIONS IN MULTI-DIMENSION SIMULATIONS

2012 ◽  
Vol 19 ◽  
pp. 90-99
Author(s):  
KUN QU ◽  
CHANG SHU ◽  
JINSHENG CAI
Keyword(s):  
Boltzmann Equation ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Lattice Boltzmann Model ◽  
Navier Stokes ◽  
Lattice Boltzmann Equation ◽  
One Dimensional ◽  
Volume Method ◽  
Boltzmann Method ◽  
Boltzmann Model

In this paper, a new flux solver was developed based on a lattice Boltzmann model. Different from solving discrete velocity Boltzmann equation and lattice Boltzmann equation, Euler/Navier-Stokes (NS) equations were solved in this approach, and the flux at the interface was evaluated with a compressible lattice Boltzmann model. This method combined lattice Boltzmann method with finite volume method to solve Euler/NS equations. The proposed approach was validated by some simulations of one-dimensional and multi-dimensional problems.

SLIP ON CURVED BOUNDARIES IN THE LATTICE BOLTZMANN MODEL

2007 ◽  
Vol 18 (01) ◽  
pp. 15-24 ◽  
Author(s):  
LAJOS SZALMÁS
Keyword(s):  
Couette Flow ◽  
Lattice Boltzmann ◽  
Slip Flow ◽  
Distribution Functions ◽  
Lattice Boltzmann Model ◽  
Momentum Balance ◽  
Curved Boundaries ◽  
Cylindrical Couette Flow ◽  
Boltzmann Method ◽  
Boltzmann Model

We present a new boundary condition in the lattice Boltzmann method to model slip flow along curved boundaries. A requirement is formulated for the distribution functions based on the tunable momentum balance at the walls, which is shown to be equivalent to the constraint on the second moment. Numerical simulation of plane Couette flow in inclined channels and cylindrical Couette flow shows excellent agreement with the analytical results in the nearly continuum regime. Orientation effects on the velocity field are completely avoided.

Impedance Boundary Condition for Lattice Boltzmann Model

2013 ◽  
Vol 13 (3) ◽  
pp. 757-768 ◽  
Author(s):  
Chenghai Sun ◽  
Franck Pérot ◽  
Raoyang Zhang ◽  
David M. Freed ◽  
Hudong Chen
Keyword(s):  
Boundary Condition ◽  
Lattice Boltzmann ◽  
Complex Geometry ◽  
Lattice Boltzmann Model ◽  
Impedance Boundary Condition ◽  
Normal Velocity ◽  
Flow Tube ◽  
Impedance Boundary ◽  
Grazing Flow ◽  
Boltzmann Model

AbstractA surface based lattice Boltzmann impedance boundary condition (BC) using Ozyoruk’s model [J. Comput. Phys., 146 (1998), pp. 29-57] is proposed and implemented in PowerFLOW. In Ozyoruk’s model, pressure fluctuation is directly linked to normal velocity on an impedance surface. In the present study, the relation between pressure and normal velocity is realized precisely by imposing a mass flux on the surface. This impedance BC is generalized and can handle complex geometry. Combined with the turbulence model in the lattice Boltzmann solver PowerFLOW, this BC can be used to model the effect of a liner in presence of a complex 3D turbulent flow. Preliminary simulations of the NASA Langley grazing flow tube and Kundt tube show satisfying agreement with experimental results.

scholarly journals Numerical Simulation of Driven Convective Heat Transfer Based Lattice Boltzmann Method in a Porous Cavity

2015 ◽  
Vol 2015 ◽  
pp. 1-8
Author(s):  
You-Sheng Xu ◽  
Rui-Min Wang ◽  
Guo-Neng Li ◽  
You-Qu Zheng
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Lattice Boltzmann Model ◽  
Published Data ◽  
Porous Cavity ◽  
Convective Thermal ◽  
Transfer Behavior ◽  
Boltzmann Method ◽  
Boltzmann Model

A lattice Boltzmann model of the uniform velocity, driven convective thermal conductivity in a porous cavity is studied. The Darcy, Richardson, and Reynolds numbers are shown to have a significant influence on the heat transfer behavior and the horizontal velocity of the flow field, while the porosity has little influence on either. The model is validated by the average Nusselt number at different Reynolds numbers, and the numerical results are in good agreement with available published data.

scholarly journals A unified lattice Boltzmann model and application to multiphase flows

2021 ◽  
Vol 379 (2208) ◽  
pp. 20200397 ◽  
Author(s):  
Kai H. Luo ◽  
Linlin Fei ◽  
Geng Wang
Keyword(s):  
Lattice Boltzmann ◽  
Model Comparison ◽  
Collision Operator ◽  
Central Moment ◽  
Lattice Boltzmann Model ◽  
Dynamics Simulation ◽  
Flow Problems ◽  
Multiple Relaxation Time ◽  
Boltzmann Method ◽  
Boltzmann Model

In this work, we develop a unified lattice Boltzmann model (ULBM) framework that can seamlessly integrate the widely used lattice Boltzmann collision operators, including the Bhatnagar–Gross–Krook or single-relation-time, multiple-relaxation-time, central-moment or cascaded lattice Boltzmann method and multiple entropic operators (KBC). Such a framework clarifies the relations among the existing collision operators and greatly facilitates model comparison and development as well as coding. Importantly, any LB model or treatment constructed for a specific collision operator could be easily adopted by other operators. We demonstrate the flexibility and power of the ULBM framework through three multiphase flow problems: the rheology of an emulsion, splashing of a droplet on a liquid film and dynamics of pool boiling. Further exploration of ULBM for a wide variety of phenomena would be both realistic and beneficial, making the LBM more accessible to non-specialists. This article is part of the theme issue ‘Progress in mesoscale methods for fluid dynamics simulation’.

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