scholarly journals Simulation of stratified flows over a ridge using a lattice Boltzmann model

2018 ◽  
Vol 20 (5) ◽  
pp. 1333-1355 ◽  
Author(s):  
Yansen Wang ◽  
Benjamin T. MacCall ◽  
Christopher M. Hocut ◽  
Xiping Zeng ◽  
Harindra J. S. Fernando
Keyword(s):  
Boundary Layer ◽  
Lattice Boltzmann ◽  
Stokes Equations ◽  
Initial Density ◽  
Stratified Flows ◽  
Lattice Boltzmann Model ◽  
Stability Parameters ◽  
Atmospheric Flows ◽  
Stably Stratified Flows ◽  
Boltzmann Model

Abstract A three-dimensional thermal lattice Boltzmann model (TLBM) using multi-relaxation time method was used to simulate stratified atmospheric flows over a ridge. The main objective was to study the efficacy of this method for turbulent flows in the atmospheric boundary layer, complex terrain flows in particular. The simulation results were compared with results obtained using a traditional finite difference method based on the Navier–Stokes equations and with previous laboratory results on stably stratified flows over an isolated ridge. The initial density profile is neutral stratification in the boundary layer, topped with a stable cap and stable stratification aloft. The TLBM simulations produced waves, rotors, and hydraulic jumps in the lee side of the ridge for stably stratified flows, depending on the governing stability parameters. The Smagorinsky turbulence parameterization produced typical turbulence spectra for the velocity components at the lee side of the ridge, and the turbulent flow characteristics of varied stratifications were also analyzed. The comparison of TLBM simulations with other numerical simulations and laboratory studies indicated that TLBM is a viable method for numerical modeling of stratified atmospheric flows. To our knowledge, this is the first TLBM simulation of stratified atmospheric flow over a ridge. The details of the TLBM, its implementation of complex boundaries and the subgrid turbulence parameterizations used in this study are also described in this article.

Hybrid lattice Boltzmann model for atmospheric flows under anelastic approximation

2021 ◽  
Vol 33 (3) ◽  
pp. 036607
Author(s):  
Y. Feng ◽  
J. Miranda-Fuentes ◽  
J. Jacob ◽  
P. Sagaut
Keyword(s):  
Lattice Boltzmann ◽  
Lattice Boltzmann Model ◽  
Atmospheric Flows ◽  
Boltzmann Model

scholarly journals Large-Eddy Simulations of Turbulent Flows around Buildings Using the Atmospheric Boundary Layer Environment–Lattice Boltzmann Model (ABLE-LBM)

2020 ◽  
Vol 59 (5) ◽  
pp. 885-899
Author(s):  
Yansen Wang ◽  
Jonathan Decker ◽  
Eric R. Pardyjak
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Turbulent Flows ◽  
Lattice Boltzmann ◽  
Laboratory Data ◽  
Lattice Boltzmann Model ◽  
Processing Unit ◽  
Laboratory Studies ◽  
Large Eddy ◽  
Boltzmann Model

ABSTRACTA three-dimensional, prognostic Atmospheric Boundary Layer Environment–Lattice Boltzmann Model (ABLE-LBM) using the multiple-relaxation-time lattice Boltzmann method was developed for large-eddy simulation of urban boundary layer atmospheric flows. In this article we describe the details of the ABLE-LBM for urban flow, its implementation of complex boundaries, and the subgrid turbulence parameterizations. As a first validation of this newly developed model, the simulation results were evaluated with two wind-tunnel datasets that were collected using particle image velocimetry and Irwin probes, respectively. The ABLE-LBM simulations use the same building layout and Reynolds numbers used in the laboratory wind tunnels. The ABLE-LBM simulations compare favorably to both laboratory studies in terms of the mean wind fields. The turbulent fluxes simulated by the model in the observational planes also agreed reasonably well with the laboratory results. The model produced urban canyon flows and vortices on the lee side and over the building tops that are similar to those of the laboratory studies in strength and location. This validation study using laboratory data indicates that our new ABLE-LBM is a viable approach for modeling atmospheric turbulent flows in urban environments. A numerical implementation using a graphics processing unit shows that real-time simulations are achieved for these two validation cases.

scholarly journals Simulating Turbulent Buoyant Flow by a Simple LES-Based Thermal Lattice Boltzmann Model

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Sheng Chen
Keyword(s):  
Lattice Boltzmann ◽  
Present Model ◽  
Stokes Equations ◽  
Lattice Boltzmann Model ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Buoyant Flow ◽  
Eddy Simulation ◽  
Thermal Lattice Boltzmann ◽  
Boltzmann Model

To simulate turbulent buoyant flow in geophysical science, where usually the vorticity-streamfunction equations instead of the primitive-variables Navier-Stokes equations serve as the governing equations, a novel and simple thermal lattice Boltzmann model is proposed based on large eddy simulation (LES). Thanks to its intrinsic features, the present model is efficient and simple for thermal turbulence simulation. Two-dimensional numerical simulations of natural convection in a square cavity were performed at high Rayleigh number varying from 104 to 1010 with Prandtl number at 0.7. The advantages of the present model are validated by numerical experiments.

INCOMPRESSIBLE MRT LATTICE BOLTZMANN MODEL WITH EIGHT VELOCITIES IN 2D SPACE

2009 ◽  
Vol 20 (07) ◽  
pp. 1023-1037 ◽  
Author(s):  
RUI DU ◽  
BAOCHANG SHI
Keyword(s):  
Relaxation Time ◽  
Lattice Boltzmann ◽  
Present Model ◽  
Incompressible Flows ◽  
Stokes Equations ◽  
Lattice Boltzmann Model ◽  
Time Model ◽  
Single Relaxation Time ◽  
Double Shear ◽  
Boltzmann Model

In this paper a two-dimensional-eight-velocity lattice Boltzmann model with multi-relaxation-time is proposed for incompressible flows, in which the equilibria in the momentum space are derived from an earlier incompressible lattice Boltzmann model with single relaxation time. Through the Chapman–Enskog expansion, the incompressible Navier–Stokes equations can be recovered. Numerical tests, including the steady Poiseuille flow, the double shear flow and the driven cavity flow, have been carried out to verify the present model. The numerical results agree well with the analytical solutions or the existing results, and it is found that the present model exhibits much better numerical stability than the single relaxation time model.

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