lattice boltzmann method

Lattice Boltzmann method (LBM) has emerged as a fast, precise, and efficient numerical solution to solve differential equations. There seems to be a dearth of research regarding the solution for groundwater flow in unconfined aquifer using LBM. Accordingly, in this study, an innovative numerical solution based on LBM was introduced to solve groundwater flow in unconfined aquifers, taking into account D2Q9 scheme. The solutions obtained from the proposed LBM were compared to results stemmed from three different unconfined groundwater problems with known solutions. Both steady and transient conditions for groundwater flow were considered in simulations. It was deduced that the proposed LBM could simulate the unconfined groundwater flow satisfactorily.

This article addresses the abilities and limitations of the Lattice Boltzmann (LB) method in solving advection-dominated mass transport problems. Several schemes of the LB method, including D2Q4, D2Q5, and D2Q9, were assessed in the simulation of two-dimensional advection-dispersion equations. The concept of Single Relaxation Time (SRT) and Multiple Relaxation Time (MRT) in addition to linear and quadratic Equilibrium Distribution Functions (EDF) were taken into account. The results of LB models were compared to the well-known Finite Difference (FD) solutions, including Explicit Finite Difference (EFD) and Crank-Nicolson (CN) methods. All LB models are more accurate than the aforementioned FD schemes. The results also indicate the high potency of D2Q5 SRT and D2Q9 SRT in describing advection-controlled mass transfer problems. The numerical artificial oscillations are observed when the Grid Peclet Number (GPN) is greater than 10, 25, 20, 25, and 10 regarding D2Q4 SRT, D2Q5 SRT, D2Q5 MRT, D2Q9 SRT and D2Q9 MRT, respectively, while the corresponding GPN values obtained for the EFD and CN methods were 2 and 5, respectively. Finally, a coupled system of groundwater and solute transport equations were solved satisfactorily using several LB models. Considering computational time, all LB models are much faster than CN method.

In the present article, Lattice Boltzmann method is utilized to simulate two-dimensional incompressible viscous flow in an open and closed microchannel (vessel). The main focus of the present research is to study physical parameters of blood flow in a vessel. To find the effect of oscillatory flow inside the vessel, we take account of the Reynolds number from 0.05 to 1.5 for numerical computation in the present manuscript in an open straight vessel. In addition, the accuracy of Poiseuille Law is investigated for blood flow in open vessel too. For this purpose, the effect of the vessel diameter and blood viscosity on the blood flow is studied numerically. As extra results, the effect of blood injection to a coronary bifurcation with two closed ends are studied. The blood pressure drop is high at the beginning of the vessel (pressure variation is high between the adjacent points along the vessel), but after the path along the vessel, the speed of dropping pressure decreases and the pressure difference between the adjoining points decreases along the vessel. Finally, the present results have been compared with the available experimental and numerical results that show good agreements.

In this work, for better understanding of microvessels disorders, mass transfer at a stenotic and the straight capillary wall in the presence of RBC motion is investigated. The immersed boundary- lattice Boltzmann method is used for this purpose. The erythrocyte is considered as an immersed biconcave shaped tissue around the capillary as a porous media. The gamma function for input concentration, which is close to the actual stenosis brain capillary, is used. The simulated results obtained for both stenosis and straight capillaries are compared. It is shown that while the RBC motion has negligibly small effects on wall mass transfer in straight capillaries, its effect is not negligible at stenosis capillaries.

In the present study, a combination of Lattice Boltzmann Method (LBM) and Smoothed Pro le Method (SPM) is used to simulate one, two, and many particles motion in a planar channel with two symmetric protuberances. LBM is applied as the fluid flow solver and SPM is used to satisfy the no-slip boundary condition at particles surfaces. Bounceback boundary conditions are used for lower and upper walls while pressure boundary conditions are applied for the fluid inlet and outlet boundaries. Horizontal, vertical, and angular velocities of particles are recorded during the simulation. It is concluded that the combined LBM-SPM can be considered as a good candidate for simulation of particle motion in a channel with stenotic geometry.

In this paper, deformation of an elastic spherical capsule suspended in a shear flow is studied in detail using Lattice Boltzmann method for fluid flow simulation, immersed boundary method for fluid-membrane interaction and finite element method for membrane force analysis. While Lattice Boltzmann method is capable of implementing inertia effects, computations were carried out for small Reynolds number in which inertia effects are negligible. Effect of three membrane constitutive equations on capsule deformation, including Neo-Hookean, zero-thickness shell approximation and Skalak’s law with different area-dilation modulus, are studied in detail. Results presented in the form of Taylor deformation parameter, inclination angle and period of tank-treading motion of capsule, show close agreement between those obtained from Neo-Hookean and zero-thickness shell approximation with previous published ones. Such agreement is partially observed for Skalak’s law implementing different area-dilation modulus. In general, behavior of all three constitutive laws are similar for nondimensional shear rates of less than 0.05 while some differences were observed for its values of 0.1 and 0.2. As an efficient computational framework, it is shown that combined Lattice Boltzmann, Immersed Boundary and Finite element method is a promising method for such flow configuration, implementing different membrane constitutive laws.

Impulsive water waves generated by landslides impose severe damages on coastal areas. Very large mass flows in the ocean can generate catastrophic tsunamis. Preventing damages to dams and coastal structures and saving lives of local people against landslide-generated waves have become increasingly important in recent years. Numerical modeling of landslide-generated waves is a challenging subject in CFD. The reason lies in difficulty of determining the interactions between the moving solids and sea water that causes complicated turbulent regimes around the moving mass and at the water surface. Submarine or aerial types of landslide can further complicate the problem. Up to now a number of numerical approaches have been proposed for predicting the behavior of flow during and after the mass movement. In this study a Lattice Boltzmann Method (LBM) based-code is employed for analyzing and simulating the impulsive water waves generated by landslides. Four experimental cases of submerged and aerial landslides have been modeled to investigate the efficiency and accuracy of the LBM code, and the obtained results are verified against experimental observations. The results indicate the capability of LBM in simulating complicated flow fields and demonstrate its superiority over numerical methods that have been used so far such as SPH and RANS.

Impulsive water waves generated by landslides impose severe damages on coastal areas. Very large mass flows in the ocean can generate catastrophic tsunamis. Preventing damages to dams and coastal structures and saving lives of local people against landslide-generated waves have become increasingly important in recent years. Numerical modeling of landslide-generated waves is a challenging subject in CFD. The reason lies in difficulty of determining the interactions between the moving solids and sea water that causes complicated turbulent regimes around the moving mass and at the water surface. Submarine or aerial types of landslide can further complicate the problem. Up to now a number of numerical approaches have been proposed for predicting the behavior of flow during and after the mass movement. In this study a Lattice Boltzmann Method (LBM) based-code is employed for analyzing and simulating the impulsive water waves generated by landslides. Four experimental cases of submerged and aerial landslides have been modeled to investigate the efficiency and accuracy of the LBM code, and the obtained results are verified against experimental observations. The results indicate the capability of LBM in simulating complicated flow fields and demonstrate its superiority over numerical methods that have been used so far such as SPH and RANS.

In this paper, the effect of a magnetic field on natural convection flow in a nanofluid-filled inclined square cavity has been analyzed by Lattice Boltzmann method (LBM). The cavity is filled with water and nanoparticles of copper at the presence of a magnetic field. This study has been carried out for the pertinent parameters in the following ranges: the Rayleigh number of the base fluid, Ra=103–105, the volumetric fractions of nanoparticles between 0 and 6% and inclined angle (θ) of the cavity between θ= -60°and 60°with interval of 30°.The Hartmann number varied from Ha=0to 30 while the uniform magnetic field is considered horizontally. Results show that the heat transfer is decreased by the increment of Hartmann number for various Rayleigh numbers and the inclined angles. Magnetic field augments the effect of nanoparticles at high Rayleigh numbers. Negative inclined angles simultaneously decline heat transfer toward θ=0°and the influence of nanoparticle.

Lattice Boltzmann Method is applied to investigate natural convection flow of a nanofluid in a concentric annulus between a cold outer square cylinder and a heated inner elliptic cylinder. In order to simulate the effective thermal conductivity and viscosity of nanofluid, Maxwell–Garnetts (MG) and Brinkman models are used, respectively. This investigation compared with other numerical methods and found to be in excellent agreement. Numerical results for the flow and heat transfer characteristics are obtained for various values of the nanoparticle volume fraction, Rayleigh numbers and eccentricity. The results show that the minimum value of enhancement of heat transfer occurs atfor but for other values of Rayleigh number it obtained at.