This application is divided into two major themes, one dealing with biofluid applications and the other related to multi-scale and- physics modeling. Common for both themes is that they make use of numerical simulations of flow and structure dynamics, and often coupled with other types of physics, such as heat transfer, fluid-structure interaction, chemical reactions and other types of physics. Biofluid dynamics This project concerns patient specific models of cardiovascular flow (heart as well as blood vessels). Apart from an increased understanding of the normal and abnormal blood flow in the human body we target intervention planning as well as follow-up and diagnostic aid for different reconstruction procedures. In order to establish such capability, a thorough understanding of normal flow conditions is required. We utilize the basic principles of fluid dynamics as well as the modelling and simulation capabilities from computational engineering and high-performance computing in combination with modern imaging modalities and image processing. With the introduction of very high-resolution CT (photon counting CT, PCCT) the need for HPC is increased significantly. Multi-scale and -physics modeling Here, a range of different multi-scale and -physics projects are to be investigated. Cavitation-induced erosion in oil-hydraulic flows is a huge concern in many fields, reducing the life expectancy of the components, and is essential to minimize. To better understand how and where these hazardous, short timescale cavitation events may occur in realistic systems requires sufficient modeling strategies at multiple tiers (from the fully/sub system to benchmark/unit problems). This calls for very high temporal and spatial resolution multiphase 3D simulations (including cavitation and erosion modelling) coupled with co-simulations of the truncated hydraulic system. Additive manufacturing makes it possible to produce complex lattice structures with high quality, which may be a paradigm shift in design for many industries, but efficient design tools are missing. We seek to therefore develop design tools based on topology and shape optimization for generating ultra-lightweight multifunctional solid-lattice designs, where high-fidelity (large/ multi-scale) multi-physics simulations play a key role; both for metamodel development (rapid design-space exploration) and validation of the final optimized design. The production of biogas plays an important role in achieving sustainable development goals, but current processes lack optimal efficiency. Here we focus on investigating different mixing processing (e.g., rheology, speed, etc.) using large-scale multi-physics CFD simulations coupled with compartmental modeling, which will be used to link CFD with kinetic models for investigating parameters that are affected by mixing.