OASIS: a coupling software for next generation earth system modelling

In this article we present a new version of the Ocean Atmosphere Sea Ice Soil coupling software (OASIS4). With this new fully parallel OASIS4 coupler we target the needs of Earth system modelling in its full complexity. The primary focus of this article is to describe the design of the OASIS4 software and how the coupling software drives the whole coupled model system ensuring the synchronization of the different component models. The application programmer interface (API) manages the coupling exchanges between arbitrary climate component models, as well as the input and output from and to files of each individual component. The OASIS4 Transformer instance performs the parallel interpolation and transfer of the coupling data between source and target model components. As a new core technology for the software, the fully parallel search algorithm of OASIS4 is described in detail. First benchmark results are discussed with simple test configurations to demonstrate the efficiency and scalability of the software when applied to Earth system model components. Typically the compute time needed to perform the search is in the order of a few seconds and is only weakly dependant on the grid size

Experiences FLOWer

Local refinements procedures aim at accurate flow solutions with a reduced impact on system resources. Additionally, the aim of the POPINDA project was the efficient implementation of a parallel, self-adaptive local refinement procedure for three-dimensional applications. The adaptation of the grids is thereby based on the insertion of grid points in regions with high discretization errors. In parallel, this results in additional communication tasks and the necessity to dynamically balance the load on the requested nodes. The local refinement procedure has been integrated in the existing multigrid algorithm of the FLOWer code, maintaining the numerical efficiency as the primary effort. In the POPINDA project, the complete procedure has been implemented and some first tests show the usefulness and perspective of the procedure

Portable Parallelization of a 3D Euler-/Navier-Stokes Solver for Complex Flows

This paper describes the portable parallelization of the FLOWer code, a large, block structured CFD solver for industrial use. Basic requirements for the parallelization are identified, and the strategies applied for its parallelization are explained. Special emphasis is put on the parallel heart of the program, the communications library CLIC-3D. Results obtained on several platforms demonstrate the success of the method chosen and allow an assessment of today's capabilities of parallel computers in CFD applications. Parallel computations of aircraft configurations of varying complexity prove that parallel computers have become operational in aircraft development

Structured Grid Solvers II - Parallelization of Block Structured FLOW Solver

This paper reviews some general considerations on the parallelization of large block structured flow solvers for production use. Parallelization is therefore not treated as an isolated subject of research, but as a tool to increase the computational power for the user and as integral part of the development environment of a CFD code. As an example the parallelization of the FLOWer code using the portable communications library CLIC-3D is given. Results of benchmark tests obtained on various computer hardware architectures demonstrate today's possibilities of parallel processing in CFD applications