Efficient Coupling of Fluid and Acoustic Interaction on Massive Parallel Systems

Abstract

We present and compare two coupling approaches for direct aeroacoustic simulations. Direct aeroacoustic simulations pose a multi-scale problem, as the generation of sound in a flow field occurs at small spatial scales with high energy, while its propagation in the farfield has to be observed on a large spatial scale with only low energy. The challenge of different scales can be addressed by employing different numerical schemes in the individual spatial areas with an interaction between them on the surfaces. Two implementation strategies of this coupling approach are presented. The first coupling strategy employs a library that allows a wide range of different applications to be coupled with minimal changes to the individual solvers. Hence, this is a very flexible approach but limited access to information and therefore cope with loss of potential performance. Further this strategy involves the handling of multiple executables on today supercomputer. This multi-solver approach requires data interpolation at the coupling interface which introduce another numerical error. In contrast, the second approach is fully integrated within one numerical framework. Thereby the solvers are invoked as a library by the coupling application and only one single applications must be handled. Tethering high order solvers, fully access to the data implies that no additional data interpolation is required which promise better numerical results. This tight integration allows for the exploitation of knowledge about internal data structures and therefore yield performance benefits accompany with less flexibility. Both strategies will be compared with respect to numerical error due to data interpolation at the coupling interface as well as scalability and performance on modern supercomputer.