The Visible Vortex - Interactive Analysis and Extraction of Vortices in Large Time-Dependent Flow Data Sets

Raphael Fuchs
The Visible Vortex - Interactive Analysis and Extraction of Vortices in Large Time-Dependent Flow Data Sets
Supervisor: Helwig Hauser
Duration: June 2006 - Oktober 2008
[thesis]

Information

Abstract

Computational simulation of physical and chemical processes has become an essential tool to tackle questions from the field of fluid dynamics. Using current simulation packages it is possible to compute unsteady flow simulations for realistic scenarios. The resulting solutions are stored in large to very large grids in 2D or 3D, frequently time-dependent, with multi-variate results from the numeric simulation. With increasing complexity of simulation results, powerful analysis and visualization tools are needed to make sense of the computed information and answer the question at hand. To do this we need new approaches and algorithms to locate regions of interest, find important structures in the flow and analyze the behavior of the flow interactively.

The main motives of this thesis are the extension of vortex detection criteria to unsteady flow and the combination of vortex detectors with interactive visual analysis. To develop an understanding for the simulation results it is necessary to compare attributes of the simulation to each other and to be able to relate them to larger structures such as vortices. It is shown how automatic feature detection algorithms can be combined with interactive analysis techniques such that both detection and analysis benefit.

By extending and integrating vortex detectors into the process of visual analysis, it becomes possible to understand the impact of vortex structures on the development of the flow. Using real-world examples from the field of engine design we discuss how vortex structures can have critical impact on the performance of a prototype. We illustrate how interactive visual analysis can support prototype design and evaluation. Furthermore, we show that taking the unsteady nature of the flow into account improves the quality of the extracted structures.

Additional Files and Images

Additional images and videos

Figure1: We illustrate some of the extensions to vortex region analysis discussed throughout this thesis. (1) We start with binary vortex detectors. It is hard to understand where the structures originate and how they are related  to the geometry. (2) Using non-binary vortex detectors we can select only the parts of the volume that  contain relevant structures. (3) By combining multiple criteria it is possible to refine the selection further and it becomes obvious that the gaskets between cylinder head and body are of critical importance. (4) Using delocalization we can further refine the selection and remove noise from the results. Figure1: We illustrate some of the extensions to vortex region analysis discussed throughout this thesis. (1) We start with binary vortex detectors. It is hard to understand where the structures originate and how they are related to the geometry. (2) Using non-binary vortex detectors we can select only the parts of the volume that contain relevant structures. (3) By combining multiple criteria it is possible to refine the selection further and it becomes obvious that the gaskets between cylinder head and body are of critical importance. (4) Using delocalization we can further refine the selection and remove noise from the results.

Additional files

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BibTeX

@phdthesis{fuchs-vortex,
  title =      "The Visible Vortex - Interactive Analysis and Extraction of
               Vortices in Large Time-Dependent Flow Data Sets",
  author =     "Raphael Fuchs",
  year =       "2008",
  abstract =   "Computational simulation of physical and chemical processes
               has become an essential tool to tackle questions from the
               field of fluid dynamics. Using current simulation packages
               it is possible to compute unsteady flow simulations for
               realistic scenarios. The resulting solutions are stored in
               large to very large grids in 2D or 3D, frequently
               time-dependent, with multi-variate results from the numeric
               simulation. With increasing complexity of simulation
               results, powerful analysis and visualization tools are
               needed to make sense of the computed information and answer
               the question at hand. To do this we need new approaches and
               algorithms to locate regions of interest, find important
               structures in the flow and analyze the behavior of the flow
               interactively.  The main motives of this thesis are the
               extension of vortex detection criteria to unsteady flow and
               the combination of vortex detectors with interactive visual
               analysis. To develop an understanding for the simulation
               results it is necessary to compare attributes of the
               simulation to each other and to be able to relate them to
               larger structures such as vortices. It is shown how
               automatic feature detection algorithms can be combined with
               interactive analysis techniques such that both detection and
               analysis benefit.  By extending and integrating vortex
               detectors into the process of visual analysis, it becomes
               possible to understand the impact of vortex structures on
               the development of the flow. Using real-world examples from
               the field of engine design we discuss how vortex structures
               can have critical impact on the performance of a prototype.
               We illustrate how interactive visual analysis can support
               prototype design and evaluation. Furthermore, we show that
               taking the unsteady nature of the flow into account improves
               the quality of the extracted structures.",
  month =      oct,
  address =    "Favoritenstrasse 9-11/186, A-1040 Vienna, Austria",
  school =     "Institute of Computer Graphics and Algorithms, Vienna
               University of Technology",
  keywords =   "Interactive Visual Analysis, Vortex Detection, Scientific
               Visualization",
  URL =        "https://www.cg.tuwien.ac.at/research/publications/2008/fuchs-vortex/",
}