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Filip Sadlo, Ronny Peikert, Mirjam Sick, Etienne Parkinson, Marc Schindler
In the last
decade, automatic detection and tracking of vortices has
become a major topic in flow visualization. Methods are based on
geometric, topological or physical vortex models were propsed.
Geometric methods use local criteria such as curvature or torsion of
streamline. Topological methods analyze critical points and their
separatrices. None of the two approaches is perfect for the full range
of scales of vortices. Geometric as well as topological methods are
based on the shape of vortices, and the same holds for the computer
vision approach to vortex extraction. In contrast to shape-based
methods, physics-based methods have been used rather sparsely and often
utilize solely the pressure data. We expect that for strongly
time-dependent velocity fields, methods based on physics are able to
give most reliable results.
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From an application point of view,
the objective of this project is to
further optimize the visualization stage in the design process for new or
upgraded hydraulic turbines and pumps. Visualization is the most
effective way of post-processing or
analyzing the CFD results. CFD simulations are computed for a series of
operating points, and often for
more than one design variant. It is therefore the main purpose of
visualization to qualitatively assess the
effect of these two parameters (operating point and design variant) on
specific flow features.
To efficiently post-process entire series of CFD results, it is
necessary to automatically detect flow
features such as vortices, cavitation, separation or recirculation. The
information from this recognition
step can then be fed into various visualization techniques, for example
it can serve to define regions-of-interest,
streamline seeds, etc..
The visualization of transient flow fields becomes more and more
important for the design engineers.
The flow in a Pelton bucket is unsteady and has to be analyzed not only
in three spatial dimensions but
also in time. The visualization of unsteady flow fields is not yet as
far developed as the visualization of
steady state flow fields.
- F. Sadlo, R. Peikert, Efficient Visualization of Lagrangian Coherent Structures by Filtered AMR Ridge Extraction, IEEE Transactions on Visualization and Computer Graphics, vol. 13, no. 6, 2007, pp. 1456-1463
[Abstract]
[BibTeX]
[PDF] [Video] [Video] [Video]
- F. Sadlo, R. Peikert, M. Sick, Visualization Tools for Vorticity Transport Analysis in Incompressible Flow, IEEE Transactions on Visualization and Computer Graphics, vol. 12, no. 5, 2006, pp. 949-956
[Abstract]
[BibTeX]
[PDF] [Video]
- F. Sadlo, R. Peikert, E. Parkinson, Vorticity Based Flow Analysis and Visualization for Pelton Turbine Design Optimization, Proceedings of IEEE Visualization '04, p. 179-186 (IEEE Vis 2004, Austin Texas, USA, October 10-15, 2004)
[Abstract]
[BibTeX]
[PDF] [Video]
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