MESOSCOPIC SPECTRA IN TWO-DIMENSIONAL DECAYING TURBULENCE

2006 ◽  
Vol 17 (04) ◽  
pp. 531-543 ◽  
Author(s):  
GÁBOR HÁZI
Keyword(s):  
Lattice Boltzmann ◽  
Particle Distribution ◽  
Power Spectra ◽  
Collision Operator ◽  
Distribution Functions ◽  
Lattice Boltzmann Model ◽  
Two Dimensional ◽  
Decaying Turbulence ◽  
The One ◽  
Boltzmann Model

Two-dimensional decaying turbulence is simulated using a lattice Boltzmann model with the Bhatnagar–Gross–Krook collision operator. Auto-power spectra of the one-velocity particle distribution functions are presented. The relation between the spectrum of the kinetic energy and the spectra of the distribution functions is given. An interpretation of the non-equilibrium spectra as a measure of the dissipation in different scales is given. A peak in the spectrum of the resting particle distribution functions is observed exactly at the ultraviolet cutoff. It is shown that the peak can be associated with enhanced acoustic activity, which might be a numerical artifact or a consequence of the compressibility of the lattice Boltzmann fluid.

scholarly journals Improved phase-field-based lattice Boltzmann models with a filtered collision operator

2019 ◽  
Vol 30 (10) ◽  
pp. 1941009
Author(s):  
Hiroshi Otomo ◽  
Raoyang Zhang ◽  
Hudong Chen
Keyword(s):  
Phase Field ◽  
Lattice Boltzmann ◽  
Density Ratio ◽  
Collision Operator ◽  
Analytic Solutions ◽  
Distribution Functions ◽  
Lattice Boltzmann Model ◽  
Low Viscosity ◽  
Lattice Boltzmann Models ◽  
Boltzmann Model

In this study, a phase-field lattice Boltzmann model based on the Allen–Cahn equation with a filtered collision operator and high-order corrections in the equilibrium distribution functions is presented. Here, we show that in addition to producing numerical results consistent with prior numerical methods, analytic solutions, and experiments with the density ratio of 1000, previous numerical deficiencies are resolved. Specifically, the new model is characterized by robustness at low viscosity, accurate prediction of shear stress at interfaces, and removal of artificial dense bubbles and rarefied droplets, etc.

scholarly journals Forcing for a Cascaded Lattice Boltzmann Shallow Water Model

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 439 ◽  
Author(s):  
Sara Venturi ◽  
Silvia Di Francesco ◽  
Martin Geier ◽  
Piergiorgio Manciola
Keyword(s):  
Shallow Water ◽  
Lattice Boltzmann ◽  
Model Performance ◽  
Lattice Boltzmann Model ◽  
Water Model ◽  
Two Dimensional ◽  
Shallow Water Model ◽  
Basic Scheme ◽  
Order Scheme ◽  
Boltzmann Model

This work compares three forcing schemes for a recently introduced cascaded lattice Boltzmann shallow water model: a basic scheme, a second-order scheme, and a centred scheme. Although the force is applied in the streaming step of the lattice Boltzmann model, the acceleration is also considered in the transformation to central moments. The model performance is tested for one and two dimensional benchmarks.

scholarly journals Recovery of Galilean invariance in thermal lattice Boltzmann models for arbitrary Prandtl number

2014 ◽  
Vol 25 (10) ◽  
pp. 1450046 ◽  
Author(s):  
Hudong Chen ◽  
Pradeep Gopalakrishnan ◽  
Raoyang Zhang
Keyword(s):  
Prandtl Number ◽  
Lattice Boltzmann ◽  
Relaxation Times ◽  
Collision Operator ◽  
Lattice Boltzmann Model ◽  
Operator Form ◽  
Prandtl Numbers ◽  
Lattice Boltzmann Models ◽  
Thermal Lattice Boltzmann ◽  
Boltzmann Model

In this paper, we demonstrate a set of fundamental conditions required for the formulation of a thermohydrodynamic lattice Boltzmann model at an arbitrary Prandtl number. A specific collision operator form is then proposed that is in compliance with these conditions. It admits two independent relaxation times, one for viscosity and another for thermal conductivity. But more importantly, the resulting thermohydrodynamic equations based on such a collision operator form is theoretically shown to remove the well-known non-Galilean invariant artifact at nonunity Prandtl numbers in previous thermal lattice Boltzmann models with multiple relaxation times.

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.

Highly Efficient Lattice Boltzmann Model for Compressible Fluids: Two-Dimensional Case

2009 ◽  
Vol 52 (4) ◽  
pp. 681-693 ◽  
Author(s):  
Chen Feng ◽  
Xu Ai-Guo ◽  
Zhang Guang-Cai ◽  
Gan Yan-Biao ◽  
Cheng Tao ◽  
...  
Keyword(s):  
Lattice Boltzmann ◽  
Compressible Fluids ◽  
Lattice Boltzmann Model ◽  
Dimensional Case ◽  
Two Dimensional ◽  
Highly Efficient ◽  
Boltzmann Model

Two-Dimensional Lattice Boltzmann Model for Droplet Impingement and Breakup in Low Density Ratio Liquids

2011 ◽  
Vol 10 (3) ◽  
pp. 767-784 ◽  
Author(s):  
Amit Gupta ◽  
Ranganathan Kumar
Keyword(s):  
Lattice Boltzmann ◽  
Weber Number ◽  
Density Ratio ◽  
Lattice Boltzmann Model ◽  
Low Density ◽  
Two Dimensional ◽  
Conservation Of Energy ◽  
Dimensional Lattice ◽  
Boltzmann Model ◽  
The Impact

AbstractA two-dimensional lattice Boltzmann model has been employed to simulate the impingement of a liquid drop on a dry surface. For a range of Weber number, Reynolds number and low density ratios, multiple phases leading to breakup have been obtained. An analytical solution for breakup as function of Reynolds and Weber number based on the conservation of energy is shown to match well with the simulations. At the moment breakup occurs, the spread diameter is maximum; it increases with Weber number and reaches an asymptotic value at a density ratio of 10. Droplet breakup is found to be more viable for the case when the wall is non-wetting or neutral as compared to a wetting surface. Upon breakup, the distance between the daughter droplets is much higher for the case with a non-wetting wall, which illustrates the role of the surface interactions in the outcome of the impact.

Sign in / Sign up

Export Citation Format

Share Document