SC²S Colloquium - November 13, 2013

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Date: November 13, 2013
Room: 02.07.023
Time: 3 pm, s.t.

Dmitry Pinaev: A Patch-Based Concept for Adaptive Lattice Boltzmann Simulations in Peano 3

The lattice Boltzmann method (LBM) is a popular method that has proven to be efficient for computing the behaviour of fluid. It has different models for two- and three-dimensional simulations and could be applied to different problems. In the last few years, the Peano framework was successfully employed in many projects such as heat transfer simulations, computational fluid dynamics problems (lattice Boltzmann and Navier-Stokes equations), molecular dynamics etc.

In this work we present an implementation of the lattice Boltzmann method based on the Peano framework with emphasis on adaptive simulations. The main goals of the project are: - Test the new version of Peano with special data management system for structures allocated on heap - Implement two-dimensional adaptive simulations with new approach to patch configuration, distinct from previous implementations - Analyze performance and correctness of resulting implementation.

This thesis provides a detailed description of using the framework for adaptive LBM simulations. We discuss key features of Peano, the structure of a typical application within the framework, and involved classes and functions. We focus on applying the patch embedding scheme and show how the communication between patches is done.

Different rescaling techniques are discussed, as well as possible grid configurations for adaptive simulations. We explain advantages of overlapping grids and discuss drawbacks of non-overlapping approach.

Finally, we give an overview on algorithm performance and provide verification plots with reference data against obtained results. In particular, the driven cavity scenarios with low Reynolds numbers (100, 400) are tested. The results of simulations show good fitting to the reference data. This work can be a basis for more sophisticated LBM implementations.

Carlos Pachajoa: Three-Dimensional Spatial Coupling of Lattice Boltzmann and Navier-Stokes Solvers

We investigate three dimensional coupling of a Navier-Stokes and a Lattice Boltzmann solver. We validate an optimization based method used to set the boundaries of the LB domain. For the resulting coupled solver, we show how information is transferred from one solver to the other. Validation results for flow between infinite parallel plates are presented, both for the steady-state and time dependent cases.