Two-Dimensional Simulations of Turbulent Flow Past a Row of Cylinders using Lattice Boltzmann Method

2017 ◽  
Vol 14 (01) ◽  
pp. 1750002 ◽  
Author(s):  
Yi-Kun Wei ◽  
Xu-Qu Hu
Keyword(s):  
Lattice Boltzmann Method ◽  
Turbulent Flows ◽  
Lattice Boltzmann ◽  
Reynolds Numbers ◽  
Passive Scalar ◽  
Two Dimensional ◽  
Flow Past ◽  
High Reynolds ◽  
An Array Of Cylinders ◽  
Boltzmann Method

Two-dimensional simulations of channel flow past an array of cylinders are carried out at high Reynolds numbers. Considering the thickness fluctuating effect on the equation of motion, a modified lattice Boltzmann method (LBM) is proposed. Special attention is paid to investigate the thickness fluctuations and vortex shedding mechanisms between 11 cylinders. Results for the velocity and vorticity differences are provided, as well as for the energy density and enstrophy spectra. The numerical results coincide very well with some published experimental data that was obtained by turbulent soap films. The spectra extracted from the velocity and vorticity fields are displayed from simulations, along with the thickness fluctuation spectrum H(k). Our results show that the statistics of thickness fluctuations resemble closely those of a passive scalar in turbulent flows.

scholarly journals Lattice Boltzmann Method Simulations of High Reynolds Number Flows Past Porous Obstacles

2019 ◽  
Vol 11 (03) ◽  
pp. 1950028 ◽  
Author(s):  
N. M. Sangtani Lakhwani ◽  
F. C. G. A. Nicolleau ◽  
W. Brevis
Keyword(s):  
Reynolds Number ◽  
Lattice Boltzmann Method ◽  
Turbulent Flows ◽  
Lattice Boltzmann ◽  
High Reynolds Number ◽  
Reynolds Numbers ◽  
Navier Stokes Equation ◽  
High Reynolds ◽  
Boltzmann Method ◽  
Reynolds Number Flows

Lattice Boltzmann Method (LBM) simulations for turbulent flows over fractal and non-fractal obstacles are presented. The wake hydrodynamics are compared and discussed in terms of flow relaxation, Strouhal numbers and wake length for different Reynolds numbers. Three obstacle topologies are studied, Solid (SS), Porous Regular (PR) and Porous Fractal (FR). In particular, we observe that the oscillation present in the case of the solid square can be annihilated or only pushed downstream depending on the topology of the porous obstacle. The LBM is implemented over a range of four Reynolds numbers from 12,352 to 49,410. The suitability of LBM for these high Reynolds number cases is studied. Its results are compared to available experimental data and published literature. Compelling agreements between all three tested obstacles show a significant validation of LBM as a tool to investigate high Reynolds number flows in complex geometries. This is particularly important as the LBM method is much less time consuming than a classical Navier–Stokes equation-based computing method and high Reynolds numbers need to be achieved with enough details (i.e., resolution) to predict for example canopy flows.

scholarly journals Lattice Boltzmann Method for Two-Dimensional Unsteady Incompressible Flow

2016 ◽  
Vol 12 (2) ◽  
pp. 122-127
Author(s):  
Juraj Mužík
Keyword(s):  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Collision Operator ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Navier Stokes Equation ◽  
Driven Cavity ◽  
Boltzmann Method ◽  
Incompressible Navier Stokes Equation

Abstract A Lattice Boltzmann method is used to analyse incompressible fluid flow in a two-dimensional cavity and flow in the channel past cylindrical obstacle. The method solves the Boltzmann’s transport equation using simple computational grid - lattice. With the proper choice of the collision operator, the Boltzmann’s equation can be converted into incompressible Navier-Stokes equation. Lid-driven cavity benchmark case for various Reynolds numbers and flow past cylinder is presented in the article. The method produces stable solutions with results comparable to those in literature and is very easy to implement.

Simulation of turbulent flows with the entropic multirelaxation time lattice Boltzmann method on body-fitted meshes

2018 ◽  
Vol 849 ◽  
pp. 35-56 ◽  
Author(s):  
G. Di Ilio ◽  
B. Dorschner ◽  
G. Bella ◽  
S. Succi ◽  
I. V. Karlin
Keyword(s):  
Turbulent Flows ◽  
Lattice Boltzmann ◽  
Numerical Data ◽  
Reynolds Numbers ◽  
Local Refinement ◽  
High Reynolds ◽  
Boltzmann Method ◽  
Dynamics Problems ◽  
Refinement Strategy ◽  
Wall Bounded Turbulence

We propose a body-fitted mesh approach based on a semi-Lagrangian streaming step combined with an entropy-based collision model. After determining the order of convergence of the method, we analyse the flow past a circular cylinder in the lower subcritical regime, at a Reynolds number$Re=3900$, in order to assess the numerical performances for wall-bounded turbulence. The results are compared to experimental and numerical data available in the literature. Overall, the agreement is satisfactory. By adopting an efficient local refinement strategy together with the enhanced stability features of the entropic model, this method extends the range of applicability of the lattice Boltzmann approach to the solution of realistic fluid dynamics problems, at high Reynolds numbers, involving complex geometries.

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