Transport phenomena in flows over complex surfaces
Carsten Wagner (from Switzerland)

Abstract
The objectives of the present studies were at first a introduction into advanced RANS models. The Delft group is one of the leading groups in the world in modeling issues of turbulent flows. Second, the stay at Delft provided deep insight into the physics of flows and numerical simulation techniques in general. A in-house code for the numerical simulation of turbulent flows (with different simulation approaches) was provided through the host group. The stay could strengthen the cooperation between the research in group in Zurich and the group in Delft and led to future interactions between the two groups. The HPC-program in general provided high-performance computing facilities which were not easily accessible for Zurich group. It could be shown that hybrid methods like detached-eddy simulation (DES) and advanced RANS models (like the one which was developed by the Delft group) can be used as design tools for engineering purposes dealing with complex turbulent transport phenomena. Furthermore, the well resolved large-eddy simulation (LES) provided physical insight into the interactions between the wall and the flow field when complex wall geometries (including separation and streamline curvature) are present. The relationship between the different transport phenomena apparent in the assessed flow situations (momentum, mass and heat transfer) could be shown. The large-eddy simulation demanded long computational times to acquire sufficient statistics of the flow field and scalar fields. The granted computational time was unfortunately not enough to compute all flow situations of interest.