ENGINEERING AND CFD

The open-source software framework waLBerla provides a common basis for stencil codes on structured grids with special focus on computational fluid dynamics with the lattice Boltzmann method. Other codes that build upon the waLBerla core are the particle dynamics module MESA-PD and the finite element framework HYTEG. Various contributors have used waLBerla to simulate a multitude of applications, such as multiphase fluid flows, electrokinetic flows, phase-field methods and fluid-particle interaction phenomena. The software design of waLBerla is specifically aimed to exploit massively parallel computing architectures with highest efficiency.

With the rapidly changing massively parallel computer architectures arising in recent years, it became a huge challenge to make efficient use of contemporary supercomputers. Project ExaStencils addresses this problem by providing an easy-to-use, multi-layered domain-specific language to the application programmer such that problems can be formulated in an intuitive way fitting to different levels of abstraction. The necessary code transformations are performed by a special-purpose compiler framework that is able to produce scalable and efficient code that runs on large supercomputers like JUQUEEN of JSC.

In order to gain a deeper understanding of the aerodynamic noise generation mechanisms and transmission for automotive applications, researchers from the Universität Erlangen leveraged HPC system SuperMUC of LRZ to develop a hybrid aeroacoustic method. The turbulent flow over a forward-facing step served as a test case for the final validation of a hybrid scheme for the computation of broadband noise, as caused typically by turbulent flows.

Researchers of the University of Erlangen applied the waLBerla Framework, a widely applicable lattice Boltzmann simulation code, on HPC system SuperMUC of LRZ to test the suitability of the software framework for different Computational Fluid Dynamics applications: One project focused on investigating collective swarming behavior of numerous self-propelled microorganisms at low Reynolds numbers, a second project implemented within waLBerla was the simulation of electron beam melting, while a third simulated the separation of charged macromolecules in electrolyte solutions inside channels of dimensions relevant for lab-on-a-chip (LoC) systems.