@article {846, title = {Analysis of the Near-Wall Flow in a Turbine Cascade by Splat Visualization}, journal = {IEEE Transactions on Visualization and Computer Graphics}, volume = {26}, year = {2020}, month = {08/2019}, pages = {719-728}, abstract = {Turbines are essential components of jet planes and power plants. Therefore, their efficiency and service life are of central engineering interest. In the case of jet planes or thermal power plants, the heating of the turbines due to the hot gas flow is critical. Besides effective cooling, it is a major goal of engineers to minimize heat transfer between gas flow and turbine by design. Since it is known that splat events have a substantial impact on the heat transfer between flow and immersed surfaces, we adapt a splat detection and visualization method to a turbine cascade simulation in this case study. Because splat events are small phenomena, we use a direct numerical simulation resolving the turbulence in the flow as the base of our analysis. The outcome shows promising insights into splat formation and its relation to vortex structures. This may lead to better turbine design in the future.}, doi = {10.1109/TVCG.2019.2934367}, url = {https://ieeexplore.ieee.org/document/8807369}, author = {Baldwin Nsonga and Gerik Scheuermann and Stefan Gumhold and Jordi Ventosa-Molina and Denis Koschichow and Jochen Fr{\"o}hlich} } @article {847, title = {Detection and Visualization of Splat and Antisplat Events in Turbulent Flows}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2020}, month = {05/2019}, pages = {1-1}, abstract = {Splat and antisplat events are a widely found phenomenon in three-dimensional turbulent flow fields. Splats are observed when fluid locally impinges on an impermeable surface transferring energy from the normal component to the tangential velocity components, while antisplats relate to the inverted situation. These events affect a variety of flow properties, such as the transfer of kinetic energy between velocity components and the transfer of heat, so that their investigation can provide new insight into these issues. Here, we propose the first Lagrangian method for the detection of splats and antisplats as features of an unsteady flow field. Our method utilizes the concept of strain tensors on flow-embedded flat surfaces to extract disjoint regions in which splat and antisplat events of arbitrary scale occur. We validate the method with artificial flow fields of increasing complexity. Subsequently, the method is used to analyze application data stemming from a direct numerical simulation of the turbulent flow over a backward facing step. Our results show that splat and antisplat events can be identified efficiently and reliably even in such a complex situation, demonstrating that the new method constitutes a well-suited tool for the analysis of turbulent flows.}, keywords = {Feature extraction, Flow visualization, Visualization techniques and methodologies}, issn = {1077-2626}, doi = {10.1109/TVCG.2019.2920157}, url = {https://ieeexplore.ieee.org/document/8727493}, author = {Baldwin Nsonga and Martin Niemann and Jochen Fr{\"o}hlich and Joachim Staib and Stefan Gumhold and Gerik Scheuermann} }