The Ernst-Mach-Institute (EMI) of the Fraunhofer-Society is dealing with a wide spectrum of subjects in the fields of applied physics, mechanical and civil engineering. The EMI department for numerical simulation supports the institute and external customers with high-performance software applications in the fields of compressible flows, structural dynamics, electro dynamics and multi-disciplinary couplings of these applications. The majority of the in-house codes are written in FORTRAN 95. Earlier performance studies of numerical simulations in terms of explicit finite element methods have shown that FORTRAN provides much better efficiency than C++. Nevertheless, potential benefits of object-oriented programming in C++ were recognized. Here we analyze the factors contributing to the code performance for the explicit finite volume scheme and show that C++ provides at least the same efficiency as FORTRAN by application of the new techniques.

Multi-Dimensional fluid-and structural dynamics problems are solved by computational methods based on Arbitrary Lagrange Euler (ALE) formulation of the continuum mechanical conservation equations. The paper presents a new modification of the radial basis function (RBF) based mesh motion scheme, which combines the RBF interpolation with the breadth-first search (BFS) algorithm. In this emerging domain, it is still unknown which algorithmic approach is the most suitable. Therefore, we realized our C ++ implementation on a high abstraction level enabling broad customization and easy extension for further algorithmic research without sacrificing performance.

Investigations of 3d transition metal (TM) compounds by means of linear dichroism in TM K-NEXAFS will be reported. At this, the decomposition of the angular-dependent NEXAFS into orbital projected components are important problems. A survey is given on methods how to extract information on the geometrical, electronic and magnetic structure from linearly polarized NEXAFS and EXAFS spectra. New results on CuO and CuPc (Copper Phthalocyanine) are reported. A reference is given to the novel method for spin-resolving of NEXAFS by analysis of resonantly scattered X-ray core lines.

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