An Exploration of numerical approaches to Boltzmann equation regarding hydrodynamics

Şahin, Alper
The Lattice Boltzmann Method (LBM) has become an alternative tool in computational fluid dynamics (CFD) techniques. While traditional CFD methods are based on Navier-Stokes equations that describe the fluid in terms of macroscopic quantities, LBM takes a mesoscopic description of the fluid thus closing the gap between macroscale and microscale. Overall, LBM provides a simple and efficient framework for simulation of fluid flows. In this approach, Boltzmann kinetic equation with BGK collision operator is discretized over a square lattice and solved to compute the evolution of a particle distribution function whose velocity moments are connected to the macroscopic primitive variables such as velocity and density. In this study, we explore two main approaches in the velocity discretization of the Boltzmann equation, namely, Galerkin and Collocation approaches. The foundations leading to these approaches are systematically laid down and some numerical examples are presented. These examples include, plane channel (Poiseuille), flow over circular and square cylinders and flow over an array of cylinders. Comparisons with available analytic and other numerical techniques show a satisfactory agreement.


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Lattice Boltzmann Method is an alternative computational method for fluid physics problems. The development of the method started in the late 1980s and early 1990s. Various numerical schemes like stream and collide, finite difference, finite element and finite volume schemes are used to solve the discrete Lattice Boltzmann Equation. Almost all of the numerical schemes in the literature are explicit schemes to exploit the natural features of the discrete Lattice Boltzmann Equation like parallelism and easy c...
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Citation Formats
A. Şahin, “An Exploration of numerical approaches to Boltzmann equation regarding hydrodynamics,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Engineering Sciences., Middle East Technical University, 2019.