Finite element lattice Boltzmann simulations of free surface flow in a concentric cylinder (original) (raw)
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… Transactions of the Royal Society of …, 2002
We use a lattice Boltzmann algorithm for liquid-gas coexistence to investigate the steady state interface profile of a droplet held between two shearing walls. The algorithm solves the hydrodynamic equations of motion for the system. Partial wetting at the walls is implemented to agree with Cahn theory. This allows us to investigate the processes which lead to the motion of the three-phase contact line. We confirm that the profiles are a function of the capillary number and a finite size analysis shows the emergence of a dynamic contact angle, which can be defined in a region where the interfacial curvature tends to zero.
Boundary condition considerations in lattice Boltzmann formulations of wetting binary fluids
Computer Physics Communications, 2011
We propose a new lattice Boltzmann numerical scheme for binary-fluid surface interactions. The new scheme combines the existing binary free energy lattice Boltzmann method [Swift et al., Phys. Rev. E 54 (1996)] and a new wetting boundary condition for diffuse interface methods in order to eliminate spurious variations in the order parameter at solid surfaces. We use a cubic form for the surface free energy density and also take into account the contribution from free energy in the volume when discretizing the wetting boundary condition. This allows us to eliminate the spurious variation in the order parameter seen in previous implementations. With the new scheme a larger range of equilibrium contact angles are possible to reproduce and capillary intrusion can be simulated at higher accuracy at lower resolution.
Lattice Boltzmann method for fluid flows
Annual review of fluid mechanics, 1998
We present an overview of the lattice Boltzmann method (LBM), a parallel and efficient algorithm for simulating single-phase and multiphase fluid flows and for incorporating additional physical complexities. The LBM is especially useful for modeling complicated boundary conditions and multiphase interfaces. Recent extensions of this method are described, including simulations of fluid turbulence, suspension flows, and reaction diffusion systems.
ANZIAM Journal, 2008
We study the methodology behind the simulation of fluid flow with up to 150,000 fully resolved rigid bodies incorporated in the flow. The simulation is performed using a 3D Lattice Boltzmann solver for the fluid flow and a so-called rigid body physics engine for the treatment of the objects. The numerical methods, the necessary extensions and the coupling between both methods are presented in detail. Furthermore, the parallelisation is discussed and performance results are given for different test cases with up to 150,000 rigid bodies on up to 1025 processor cores. The approach enables a detailed simulation of large scale particulate flows, which are relevant for many industrial applications.
Lattice Boltzmann simulations of incompressible liquid-gas systems on partial wetting surfaces
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2011
A three-dimensional Lattice Boltzmann two-phase model capable of dealing with large liquid and gas density ratios and with a partial wetting surface is introduced. This is based on a high density ratio model combined with a partial wetting boundary method. The predicted three-dimensional droplets at different partial wetting conditions at equilibrium are in good agreement with analytical solutions. Despite the large density ratio, the spurious velocity around the interface is not substantial, and is rather insensitive to the examined liquid and gas density and viscosity ratios. The influence of the gravitational force on the droplet shape is also examined through the variations of the Bond number, where the droplet shape migrates from spherical to flattened interface in tandem with the increase of the Bond number. The predicted interfaces under constant Bond number are also validated against measurements with good agreements.
A study of fluid interfaces and moving contact lines using the Lattice Boltzmann method
Communications in Computational Physics, 2013
We study the static and dynamical behavior of the contact line between two fluids and a solid plate by means of the Lattice Boltzmann method (LBM). The different fluid phases and their contact with the plate are simulated by means of standard Shan-Chen models. We investigate different regimes and compare the multicomponent vs. the multiphase LBM models near the contact line. A static interface profile is attained with the multiphase model just by balancing the hydrostatic pressure (due to gravity) with a pressure jump at the bottom. In order to study the same problem with the multicomponent case we propose and validate an idea of a body force acting only on one of the two fluid components. In order to reproduce results matching an infinite bath, boundary conditions at the bath side play a key role. We quantitatively compare open and wall boundary conditions and study their influence on the shape of the meniscus against static and lubrication theory solution.
Meshless lattice Boltzmann method for the simulation of fluid flows
Physical Review E, 2015
A meshless lattice Boltzmann numerical method is proposed. The collision and streaming operators of the lattice Boltzmann equation are separated, as in the usual lattice Boltzmann models. While the purely local collision equation remains the same, we rewrite the streaming equation as a pure advection equation and discretize the resulting partial differential equation using the Lax-Wendroff scheme in time and the meshless local Petrov-Galerkin scheme based on augmented radial basis functions in space. The meshless feature of the proposed method makes it a more powerful lattice Boltzmann solver, especially for cases in which using meshes introduces significant numerical errors into the solution, or when improving the mesh quality is a complex and time-consuming process. Three well-known benchmark fluid flow problems, namely the plane Couette flow, the circular Couette flow, and the impulsively started cylinder flow, are simulated for the validation of the proposed method. Excellent agreement with analytical solutions or with previous experimental and numerical results in the literature is observed in all the simulations. Although the computational resources required for the meshless method per node are higher compared to that of the standard lattice Boltzmann method, it is shown that for cases in which the total number of nodes is significantly reduced, the present method actually outperforms the standard lattice Boltzmann method.
An improved immersed-boundary algorithm for fluid-solid interaction in Lattice-Boltzmann simulations
Latin American Applied Research, 2013
An improved algorithm combining the features of the lattice-Boltzmann and the immersedboundary methods is presented. Following previous formulations, the method represents a fluid constrained by flexible boundaries by means of a force term acting on the cells adjacent to the boundary, which in turn is moved by the fluid. The present algorithm introduces a more efficient iteration procedure to calculate the fluid-boundary interaction, which facilitates the implementation and improves performance. The simulations were validated against experimental and analytical data showing good agreement and demonstrating the performance of the method to simulate different kind of fluid-solid interaction. Keywords Immersed boundary method, Lattice Boltzmann method, fluid-structure interaction.