Gerd Teike

Investigation of the LES WALE turbulence model within the lattice Boltzmann framework

Turbulence models which can perform the transition from laminar flow to fully developed turbulent flow are of key importance in industrial applications. A promising approach is the LES WALE model, which can be used without wall functions or global damping functions. The model produces an efficient and fast scheme due to its algebraic character. Additionally, its prediction of the transition from laminar to turbulent regimes has shown promising results. In this work, the LES WALE model is investigated within the lattice Boltzmann framework. For validation purposes, various test cases are presented. First, a channel flow at a Reynolds number of 6876 is investigated. Secondly, the flow around a wall-mounted cube at various Reynolds numbers is determined. The flow regime varies from laminar, to transitional, to fully turbulent conditions at a Reynolds number of 40,000 with respect to the cube height.

Multiscale Lattice–Boltzmann Approach for Electrophoretic Particle Deposition

In this work, a gas-particle flow over a structured sensor surface is numerically investigated. A system of parallel electrodes with an applied voltage is distributed on top of a nonconducting flat surface. The considered submicron particles (size range 25–200 nm) are electrically charged. The simulation takes into account the interaction between particle motion, fluid flow and electrical field causing the particles to deposit on the surface. As a result, dendrite microstructures of particles start growing on the electrode surface. To model these effects in detail the numerical simulations are carried out on a mesh with very high resolution of up to Δx = 0.5 μm. The fluid-flow is calculated with the Lattice–Boltzmann method incorporating automatic local grid refinement. The Laplacian equation describing the electrical field is solved by a finite-difference-scheme. The particle movement is calculated by the Lagrangian point-particle approach, accounting for drag force, Brownian motion, and Coulomb forces. Results of particle transport and dynamics of particle deposition are presented for different applied voltage, electrode configurations, flow velocities, and particle sizes.

Lattice-Boltzmann Method with Dynamic Grid Refinement for Simulating Particle Deposition on a Single Fibre

In this work a numerical approach to predict the deposition behaviour of nano-scale particles on the surface of a single fibre by resolving the resulting dendrite-like particle structures in detail is presented. The gas flow simulation is carried out by a two-dimensional Lattice-Boltzmann method, which is coupled with a Lagrangian approach for the particle motion. To decrease calculation time and system requirements the Lattice-Boltzmann model is extended to allow for local grid refinement. Because of the a priori unknown location of deposition, the simulation procedure starts on a coarse mesh which is then locally refined in a fully adaptive way in regions of accumulated particles. After each deposition the fluid flow is recalculated in order to resolve the coupling of the flow with the growing particle structures correctly. For the purpose of avoiding unphysical blocking of flow by growing particle dendrites the Lattice-Boltzmann method is extended to permeable cells in these regions using the Brinkmann...