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Chair for System Simulation (Department of Computer Science 10)
Description and Features
Dept. of Computer Science  >  Computer Science 10  >  Research  >  Projects  >  waLBerla  >  Description


Supercomputer architecture is moving quickly to multi-core and many- core architectures. An additional trend is the increasing use of special purpose accelerators, e.g. in form of graphics cards, the Cell processor, or reconfigu- rable hardware. This has the potential to deliver unprecedented performance at lower cost and reduced power consumption. However, this trend opens many unanswered questions on how these devices can be use effectively in real life supercomputing applications, since these accelerators are only effec- tive on certain algorithmic structures that exhibit a high degree of regularity and they are inefficient or very difficult to program for others. At the LSS we have developed (partly with KONWIHR support) application software, whose basic structure supports heterogeneous architectures. For this project we will focus on the waLBerla framework for simulating complex flows that have a wide range of applications [4, 5]. The software waLBerla is designed such that it distinguishes between modules that require complex algorithmic logic and regular structures that can exploit a very high degree of parallelism. While the latter parts are very well suited for a potential use of multi-core parallelism and accelerator technologies, the algorithmically more complex parts also can be run on the conventional parts of a heterogeneous system. We therefore propose to extend waLBerla in order to exploit current and future heterogeneous multi-core architectures.Solving problems in present-day simulation is becoming more and more complex. Both the number of physical effects taken into account and the complexity of the associated software development process increase. In order to meet these growing demands, the Chair for System Simulation (LSS) developed the massively parallel and flexible simulation framework waLBerla (widely applicable Lattice Boltzmann solver from Erlangen). Originally, the framework has been centered around the Lattice-Boltzmann method for the simulation of fluid scenarios. Meanwhile, its usability is not only limited to this algorithm but it is also suitable for a wide range of applications, based on structured grids. For example, an efficient multigrid solver for partial differential equations has been integrated. Next to the basic requirements of easy adaptivity and extensibility for new fluid problems, the waLBerla project also aims at physical correctness and high performance. A particular feature is the simulation of large ensembles of geometrically fully resolved, and arbitrarily shaped particles within fluid flows. Even on 294912 cores, it is possible to gain an efficieny of more than 95%. Hence, waLBerla is a comprehensive program rich in features as well as a library for the easy development of new applications based on fluid simulation. Thus, it meets the requirements of scientific researchers, performance optimizers, code developers as well as for industrial cooperations.


  • Free Surface Flows

  • Regina Ammer Daniela Anderl Simon Bogner Matthias Markl

    Two-phase flows are apparent in our everyday life and many industrial applications. Within waLBerla, the simulation of free surfaces copes with different scientific problems in this field. Simulation of bubbly flows and foams can be applied to metal foaming or food froth. Wetting models enable the simulation of printable circuits and labs on a chip. Applied on porous media, oil extraction, water in fuel cells or diapers can be simulated.
    Figure 1: Liquid water drop on a surface with two different contact angles (red: hydrophobic (100°), green: hydrophilic (47°)).
    Figure 2: Drop hit by a bullet (no gravity).
  • Particulate Flows

  • Dominik Bartuschat Kristina Pickl

    Within the waLBerla project a simulation methodology has been developed for the simulation of physically realistic particulate flows, such as sedimentation, erosion or segregation processes, involving millions of fully resolved, arbitrarily shaped particles.

    Figure 3: The house of the bear: fluid structure interaction can be simulated very stable.
    Figure 4: Sedimentation process with bodies of different masses (red: high mass, grey: low mass).
  • HPC Software Design

  • Martin Bauer Christian Godenschwager Florian Schornbaum

    The thorough and systematic design of software components for use within HPC projects is of utmost importance for the correctness and efficiency. Also, proper HPC software design is a prerequisite to tackle the enormous complexity of the target applications. In this project the necessary software infrastructure for both the waLBerla and the pe (physics engine) project is developed.
    Figure 5: Sweep concept: work steps are subdivided into preprocessing, actual work and postprocessing step.
    Figure 6: Patch and block design: supports massively parallel simulations and load balancing.
  Contact Last modified: 2013-01-23 17:38   kp