The characteristic vortex formation in the ventricles is believed to be affected at an early stage of heart diseases. First, post-processing of patient-specific data has to be standardised. The chosen methods, a combination of Eulerian and Lagrangian techniques, are characterised by means of necessary spatial and temporal resolutions. Second, the goal is to find the best cost-benefit approach for modelling of the mitral valve, as it affects vortex formation and progression in the left ventricle.

Die wachsende Nachfrage nach höherer Leistung und geringerer Umweltbelastung durch tribologische Geräte hat zur Entwicklung strukturierter Oberflächen geführt, die Reibungsverluste und Verschleißphänomene reduzieren können. Ein großer Teil der tribologischen Forschung an solchen Oberflächen beruht auf experimentellen Untersuchungen, die auf Pin-on-Disc-Tribometern basieren. Ziel der Arbeit ist, die numerische Darstellung dieser Experimente und die Untersuchung des Einflusses von Texturen. The growing demand for higher performance and lower environmental impactof tribological devices has led to the development of textured surfaces as efficient way to reduce friction losses and wear. Great part of the tribological research of such engineered surfaces relies on experimental set-ups based on pin-on-disc tribometers. The aim of the present work is the numerical representation of such kind of experimental set-ups in order to study the influence of textures in the hydrodynamic regime.

The present work delivers a versatile, accurate and reliable wind tunnel facility that is particularly developed to test different flow control techniques for drag reduction in precisely adjustable test conditions. Skin friction changes of 0.4% are resolved, which is comparable to the most accurate reported studies in liquids. this high accuracy is verified through a comprehensive uncertainty analysis. Subsequently, various passive and active flow control strategies are investigated.

This work explores the mechanics of turbulent propagation in dilute polymer solutions with the objective of increasing the current understanding on turbulent propagation not only of this particular kind of flow, but also of Newtonian turbulent flows in general. By means of Direct Numerical Simulations of planar turbulent/non-turbulent interfaces, the phenomenon of turbulence propagation has been studied in its full range of turbulent scales.

The work presents an attempt to improve the understanding of reactive drag reducing control of near-wall turbulence with respect to limitations present in a realistic application scenario. The reference reactive control scheme of opposition control is studied using direct numerical simulation through the consideration of various application oriented restrictions, i.e. local control application, limited spatial and temporal resolution of the scheme, sensor noise and control elements arrangement.

This work aims at developing a strategy how the energy which has to be applied to transport incompressible and Newtonian fluids through straight ducts can be reduced. Based on the physical properties of laminar and turbulent flow, models are derived which theoretically lead to the reduction of the dissipated energy. The possibility to implement the proposed state due to appropriate design aspects in the cross section shape of the duct is investigated based on numerical simulations of the flow.