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Fluid Dynamics Seminar

Monday, Nov. 8, 2010, 4:00 PM
Cullimore, Room 611
New Jersey Institute of Technology

Unstructured Lattice Boltzmann Method for Single- and Two-phase Flows

Taehun Lee

Department of Mechanical Engineering and CUNY Energy Institute, City College of City University of New York

Abstract

The lattice Boltzmann method (LBM) is derived from the discrete Boltzmann equation by discretizing it on uniform rectangular mesh and usually comprises collision and streaming steps. While this greatly facilitates numerical procedure, it limits shapes of the computational domain that LBM can be applied to. This limitation could substantially increase computational effort for flows of boundary-layer type and in complex geometries. To overcome geometric constraint of LBM and to improve its numerical stability at high Reynolds number, we have recently proposed Galerkin finite element (FE) LBM and spectral element discontinuous Galerkin (SEDG) LBM. In these computational frameworks, LBM is regarded as a special space-time discretization of the discrete Boltzmann equation in the characteristic direction, and can be solved by higher-order accurate schemes on unstructured mesh. In this presentation, a brief introduction to the temporal and spatial discretizations of the discrete Boltzmann equation will be given, with emphasis on the Galerkin FE and SEDG approximations on unstructured mesh. Applications of the new LBM will be discussed in the simulations of shear layers, Drop-on-demand inkjet drop impact, liquid-bridge vibration under microgravity, and free surface flow in a concentric cylinder.