TY - JOUR A1 - Kasten, Jens A1 - Reininghaus, Jan A1 - Hotz, Ingrid A1 - Hege, Hans-Christian A1 - Noack, Bernd A1 - Daviller, Guillaume A1 - Morzyński, Marek T1 - Acceleration feature points of unsteady shear flows JF - Archives of Mechanics N2 - A framework is proposed for extracting features in 2D transient flows, based on the acceleration field to ensure Galilean invariance. The minima of the acceleration magnitude, i.e. a superset of the acceleration zeros, are extracted and discriminated into vortices and saddle points --- based on the spectral properties of the velocity Jacobian. The extraction of topological features is performed with purely combinatorial algorithms from discrete computational topology. The feature points are prioritized with persistence, as a physically meaningful importance measure. These features are tracked in time with a robust algorithm for tracking features. Thus a space-time hierarchy of the minima is built and vortex merging events are detected. The acceleration feature extraction strategy is applied to three two-dimensional shear flows: (1) an incompressible periodic cylinder wake, (2) an incompressible planar mixing layer and (3) a weakly compressible planar jet. The vortex-like acceleration feature points are shown to be well aligned with acceleration zeros, maxima of the vorticity magnitude, minima of pressure field and minima of λ2. Y1 - 2016 VL - 68 IS - 1 SP - 55 EP - 80 ER - TY - CHAP A1 - Kuhn, Alexander A1 - Engelke, Wito A1 - Flatken, Markus A1 - Hege, Hans-Christian A1 - Hotz, Ingrid T1 - Topology-based Analysis for Multimodal Atmospheric Data of Volcano Eruptions T2 - Topological Methods in Data Analysis and Visualization IV Y1 - 2017 U6 - https://doi.org/10.1007/978-3-319-44684-4_2 SP - 35 EP - 50 PB - Springer CY - Cham, Schweiz ER - TY - CHAP A1 - Hlawitschka, Mario A1 - Hotz, Ingrid A1 - Kratz, Andrea A1 - Marai, G. Elisabeta A1 - Moreno, Rodrigo A1 - Scheuermann, Gerik A1 - Stommel, Markus A1 - Wiebel, Alexander A1 - Zhang, Eugene ED - Westin, Carl-Frederic ED - Burgeth, Bernhard ED - Vilanova, Anna T1 - Top Challenges in the Visualization of Engineering Tensor Fields T2 - Visualization and Processing of Tensors and Higher-Order Descriptors for Multi-Field Data Y1 - 2014 SP - 3 EP - 15 PB - Springer ER - TY - GEN A1 - Kasten, Jens A1 - Reininghaus, Jan A1 - Hotz, Ingrid A1 - Hege, Hans-Christian A1 - Noack, Bernd A1 - Daviller, Guillaume A1 - Morzyński, Marek T1 - Acceleration feature points of unsteady shear flows N2 - A framework is proposed for extracting features in 2D transient flows, based on the acceleration field to ensure Galilean invariance. The minima of the acceleration magnitude, i.e. a superset of the acceleration zeros, are extracted and discriminated into vortices and saddle points --- based on the spectral properties of the velocity Jacobian. The extraction of topological features is performed with purely combinatorial algorithms from discrete computational topology. The feature points are prioritized with persistence, as a physically meaningful importance measure. These features are tracked in time with a robust algorithm for tracking features. Thus a space-time hierarchy of the minima is built and vortex merging events are detected. The acceleration feature extraction strategy is applied to three two-dimensional shear flows: (1) an incompressible periodic cylinder wake, (2) an incompressible planar mixing layer and (3) a weakly compressible planar jet. The vortex-like acceleration feature points are shown to be well aligned with acceleration zeros, maxima of the vorticity magnitude, minima of pressure field and minima of λ2. T3 - ZIB-Report - 15-65 Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-58397 SN - 1438-0064 ER - TY - GEN A1 - Kasten, Jens A1 - Hotz, Ingrid A1 - Hege, Hans-Christian ED - Peikert, Ronald ED - Hauser, Helwig ED - Carr, Hamish ED - Fuchs, Raphael T1 - On the Elusive Concept of Lagrangian Coherent Structures T2 - Topological Methods in Data Analysis and Visualization II Y1 - 2012 U6 - https://doi.org/10.1007/978-3-642-23175-9_14 SP - 207 EP - 220 PB - Springer ER - TY - JOUR A1 - Zobel, Valentin A1 - Reininghaus, Jan A1 - Hotz, Ingrid T1 - Generalized Heat Kernel Signature JF - Journal of WSCG, International Conference on Computer Graphics, Visualization and Computer Vision Y1 - 2011 SP - 93 EP - 100target ER - TY - GEN A1 - Kasten, Jens A1 - Reininghaus, Jan A1 - Oberleithner, Kilian A1 - Hotz, Ingrid A1 - Noack, Bernd A1 - Hege, Hans-Christian T1 - Flow over a Cavity – Evolution of the Vortex Skeleton Y1 - 2010 PB - Visualization at 28th Annual Gallery of Fluid Motion exhibit, held at the 63th Annual Meeting of the American Physical Society, Division of Fluid Dynamics (Long Beach, CA, USA, November 21-23, 2010). ER - TY - JOUR A1 - Kasten, Jens A1 - Petz, Christoph A1 - Hotz, Ingrid A1 - Hege, Hans-Christian A1 - Noack, Bernd A1 - Tadmor, Gilead T1 - Lagrangian Feature Extraction of the Cylinder Wake JF - Physics of Fluids Y1 - 2010 U6 - https://doi.org/10.1063/1.3483220 VL - 22 IS - 9 SP - 091108 ER - TY - CHAP A1 - Kratz, Andrea A1 - Kettlitz, Nino A1 - Hotz, Ingrid T1 - Particle-Based Anisotropic Sampling for Two-Dimensional Tensor Field Visualization T2 - Vision Modeling and Visualization (VMV’11) Y1 - 2011 SP - 145 EP - 152 PB - Eurographics Association target ER - TY - GEN A1 - Kratz, Andrea A1 - Meyer, Björn A1 - Hotz, Ingrid ED - Hagen, Hans T1 - A Visual Approach to Analysis of Stress Tensor Fields T2 - Scientific Visualization: Interactions, Features, Metaphors Y1 - 2011 UR - http://drops.dagstuhl.de/opus/volltexte/2011/3296 U6 - https://doi.org/10.4230/DFU.Vol2.SciViz.2011.188 VL - 2 SP - 188 EP - 211 PB - Schloss Dagstuhl–Leibniz-Zentrum fuer Informatik CY - Dagstuhl, Germany ER -