Numerical Simulation for Flow over Two Circular Cylinders in Micro Channel with Lattice Boltzmann Method

2014 ◽  
Vol 670-671 ◽  
pp. 747-750
Author(s):  
Zhi Jun Gong ◽  
Jiao Yang ◽  
Wen Fei Wu
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Recirculation Zone ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Circular Cylinders ◽  
Micro Channel ◽  
Zone Length ◽  
Spacing Ratio ◽  
Boltzmann Method

For indepth study on flow characteristics for fluid bypass obstacles in micro-channel, the Lattice Boltzmann Method (LBM) was used to simulate fluid flow over two circular cylinders in side-by-side arrangement of a micro-channel. The velocity distribution and recirculation zone length under different Reynolds numbers (Re = 0~100) and different spacing ratio (H/D= 0~2.0) were obtained. The results show that the pattern of flow and the size of recirculation zone in the micro-channel depend on the combined effect of Re and H/D.

Numerical acoustic simulation of flow around circular cylinders based on Lattice Boltzmann method and Ffowcs Williams-Hawkings acoustic equation

2018 ◽  
Vol 07 (01n02) ◽  
pp. 1850010
Author(s):  
H. R. Hu ◽  
C. Zhang ◽  
X. Wang
Keyword(s):  
Lattice Boltzmann Method ◽  
Sound Pressure Level ◽  
Lattice Boltzmann ◽  
Sound Pressure ◽  
Vertical Direction ◽  
Pressure Level ◽  
Circular Cylinders ◽  
Acoustic Equation ◽  
Spacing Ratio ◽  
Boltzmann Method

Based on the GPU acceleration technique, Lattice Boltzmann method (LBM) and Ffowcs Williams-Hawkings (FW-H) acoustic equation are adopted to simulate the noise generated by flow around fixed and rotating circular cylinders when Reynolds number (Re) is 200. The results show that the sound pressure level has a peak in the vertical direction and it is higher than that in the streamwise direction. The maximum sound pressure level is significantly reduced when the cylinder rotates due to the suppression of vortex shedding compared to the case of a fixed cylinder. For tandem cylinders, the maximum sound pressure level in the vertical direction increases as the spacing ratio increases, and for parallel cylinders, it decreases as the spacing ratio increases. In addition, when using graphic processing unit (GPU), the computational efficiency is improved greatly and the speed-up reaches nearly 100.

Study of unsteady separated fluid flows using a multi-block lattice Boltzmann method

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Eslam Ezzatneshan
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Fluid Flows ◽  
Reynolds Numbers ◽  
Small Scale ◽  
Near Wake ◽  
Content Type ◽  
Boltzmann Method

Purpose Numerical simulations are performed for studying the vorticity dynamics of a dipole colliding with the wall in a bounded flow and the wake structure and separated flow properties past a circular cylinder at the values of Reynolds numbers. Design/methodology/approach The near wake statistics of separated fluid flows are investigated by using the lattice Boltzmann method (LBM) in a two-dimensional framework. A multi-block technique is applied to accurately resolve the flow characteristics by the grid refinement near the wall and preserve the stability of the numerical solution at relatively high Reynolds numbers. Findings The results show that the rolling-up of the boundary layer occurs due to the shear-layer instabilities near the surface which causes a boundary layer detachment from the wall and consequently leads to the formation of small-scale vortices. These shear-layer vortices shed at higher frequencies than the large-scale Strouhal vortices which result in small-scale high-frequency fluctuations in the velocity field in the very near wake. The present study also demonstrates that the efficiency of the multi-block LBM used for predicting the statistical features of flow problems is comparable with the solvers based on the Navier-Stokes equations. Practical implications Studying the separated flow characteristics in aerospace applications. Originality/value Applying a multi-block lattice Boltzmann method (LBM) for simulation of separated fluid flows at high-Reynolds numbers. Studying of the near wake statistics of unsteady separated fluid flows using the multi-block LBM. Comparison of flow characteristics obtained based on the LBM with those of reported based on the Navier-Stokes equations.

Numerical study of capillary-driven flow in square micro-channel by lattice Boltzmann method

2019 ◽  
Vol 19 (1) ◽  
pp. 12
Author(s):  
Mohamed El Amine Ben Amara ◽  
Patrick Perré ◽  
Abdolreza Kharaghani ◽  
Sassi Ben Nasrallah
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Numerical Study ◽  
Micro Channel ◽  
Boltzmann Method

scholarly journals Large-scaled simulation on the coherent vortex evolution of a jet in a cross-flow based on lattice Boltzmann method

2015 ◽  
Vol 19 (3) ◽  
pp. 977-988 ◽  
Author(s):  
Yanqin Shangguan ◽  
Xian Wang ◽  
Yueming Li
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Flow Characteristics ◽  
Cross Flow ◽  
Hairpin Vortex ◽  
Graphic Processing Units ◽  
Computational Performance ◽  
Good Ability ◽  
Secondary Vortices ◽  
Boltzmann Method

Large eddy simulation (LES) is performed on a jet issued normally into a cross-flow using lattice Boltzmann method (LBM) and multiple graphic processing units (multi-GPUs) to study the flow characteristics of jets in cross-flow (JICF). The simulation with 8 1.50?10 grids is fulfilled with 6 K20M GPUs. With large-scaled simulation, the secondary and tertiary vortices are captured. The features of the secondary vortices and the tertiary vortices reveal that they have a great impact on the mixing between jet flow and cross-flow. The qualitative and quantitative results also indicate that the evolution mechanism of vortices is not constant, but varies with different situations. The hairpin vortex under attached jet regime originates from the boundary layer vortex of cross-flow. While, the origin of hairpin vortex in detached jet is the jet shear-layer vortex. The mean velocities imply the good ability of LBM to simulate JICF and the large loss of jet momentum in detached jet caused by the strong penetration. Besides, in our computation, a high computational performance of 1083.5 MLUPS is achieved.

A Micro-Channel Flow and Heat Transfer Study by Lattice Boltzmann Method

2003 ◽  
Author(s):  
Ru Yang ◽  
Chin-Sheng Wang
Keyword(s):  
Heat Transfer ◽  
Lattice Boltzmann Method ◽  
Channel Flow ◽  
Lattice Boltzmann ◽  
Slip Flow ◽  
Navier Stokes ◽  
Micro Channel ◽  
Parallel Plates ◽  
Boltzmann Method ◽  
Good Agreement

A Lattice Boltzmann method is employed to investigate the flow characteristics and the heat transfer phenomenon between two parallel plates separated by a micro-gap. A nine-velocity model and an internal energy distribution model are used to obtain the mass, momentum and temperature distributions. It is shown that for small Knudsen numbers (Kn), the current results are in good agreement with those obtained from the traditional Navier-Stokes equation with non-slip boundary conditions. As the value of Kn is increased, it is found that the non-slip condition may no longer be valid at the wall boundary and that the flow behavior changes to one of slip-flow. In slip flow regime, the present results is still in good agreement with slip-flow solution by Navier Stokes equations. The non-linear nature of the pressure and friction distribution for micro-channel flow is gieven. Finally, the current investigation presents a prediction of the temperature distribution for micro-channel flow under the imposed conditions of an isothermal boundary.

NUMERICAL SIMULATION OF THE FLOWS OVER TWO TANDEM CYLINDERS BY LATTICE BOLTZMANN METHOD

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1551-1554 ◽  
Author(s):  
XIAOKE KU ◽  
JIANZHONG LIN
Keyword(s):  
Numerical Simulation ◽  
Pressure Distribution ◽  
Lattice Boltzmann Method ◽  
Stagnation Point ◽  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Effective Distance ◽  
Minimum Pressure ◽  
Tandem Cylinders ◽  
Boltzmann Method

Flows over two tandem cylinders are simulated numerically based on the lattice Boltzmann method. The pressure distribution on the cylinders for varying distance between the two cylinders at different Reynolds numbers is depicted. The results show that the minimum pressure on the front cylinder does not occur at the stagnation point because of the existence of the back cylinder. The distance between the point with minimum pressure and the stagnation point becomes large with increasing Re number. The minimum pressure on the back cylinder varies with the distance between the two cylinders. The effective distance of interaction between two cylinders is less than 4d with d being the diameter of the cylinder.

Simulation of Flow Past a Square Cylinder by Parallel Lattice Boltzmann Method using Multi-Relaxation-Time Scheme

2006 ◽  
Vol 22 (1) ◽  
pp. 35-42 ◽  
Author(s):  
J.-S. Wu ◽  
Y.-L. Shao
Keyword(s):  
Relaxation Time ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Numerical Results ◽  
Channel Height ◽  
Blockage Ratio ◽  
Square Cylinder ◽  
Single Relaxation Time ◽  
Boltzmann Method

AbstractThe flows past a square cylinder in a channel are simulated using the multi-relaxation-time (MRT) model in the parallel lattice Boltzmann BGK method (LBGK). Reynolds numbers of the flow are in the range of 100 ∼ 1,850 with blockage ratio, 1/6, of cylinder height to channel height, in which the single-relaxation-time (SRT) scheme is not able to converge at higher Reynolds numbers. Computed results are compared with those obtained using the SRT scheme where it can converge. In addition, computed Strouhal numbers compare reasonably well with the numerical results of Davis (1984).

Flow Characteristics of Rarified Gases in Micro-Grooved Channels by the Lattice-Boltzmann Method

2008 ◽  
Author(s):  
Amador M. Guzma´n ◽  
Andre´s J. Di´az ◽  
Luis E. Sanhueza ◽  
Rodrigo A. Escobar
Keyword(s):  
Numerical Simulations ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Pressure Ratio ◽  
Plane Channel ◽  
Flow Characteristics ◽  
Numerical Results ◽  
Knudsen Numbers ◽  
Channel Configuration ◽  
Boltzmann Method

The flow characteristics of a rarified gas have been investigated in microgrooved channels. The governing Boltzmann Transport Equation (BTE) is solved by the Lattice-Boltzmann method (LBM) for the Knudsen number range of 0.01–0.1. First, the compressibility and rarified effects are investigated in a plane channel by performing numerical simulations for different Knudsen numbers, pressure ratio and accommodation coefficients with the objective of validating the computational code used in this investigation and determining the transition characteristics from the macro to microscale. The numerical predictions are compared to existing analytical and numerical results. Then, numerical simulations are performed for microgrooved channels for the Knudsen numbers range of [0.01–0.1]. Different meshes are used for preserving numerical stabilities and obtaining accurate enough numerical results. For the microgrooved channel configuration, the fluid characteristics are determined in terms of pressure ratio and Knudsen numbers. The numerical results are compared to existing analytical predictions and numerical results obtained from plane channel and one cavity simulations.

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