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Direct Numerical Simulation of Turbulent Flame Quenching by Fine Water Droplets

Pseudocolor plots of temperature fields (Left) and vorticity (Right) from a simulation of flame extinction by water spray. Image kindly provided by Paul Arias (U. Mich), Hong Im (U. Mich), Arnaud Trouve (U. Maryland) and Praveen Narayanan (U. Maryland).

The NERSC Analytics team has been supporting the INCITE12 research group with technical consulting advice on getting their simulation data imported into VisIt, basics of how to use VisIt and recommendations for effective display of simulation data. Some Tecplot/Ensight file format issues were identified in the process, and a number of VisIt tutorials were developed to help the group develop visualizations on their own.

The following tutorials were developed to get the INCITE12 collaborators. VisIt is a powerful visualization and analytics software package developed by LLNL and currently in active use/development by a number of research institutions.

Tutorial 1: Loading your dataset, simple interactions

Tutorial 2: Using Plots, Operators and some analysis tools

Tutorial 3: Loading multiple datasets

Tutorial 4: Particle Plots

Tutorial 5: Creating movies in VisIt

File Format Issues
Issues with tecplot. The first issue we ran into was that the tecplot file specification DT=(DOUBLE DOUBLE ..) listed more variables than were actually written out in the file (x/y/u/v/etc). After fixing that problem, we realized that the VisIt tecplot reader had an issue with interpreting the contents of the dataset if both x and y variables had a unit attribute next to them. So "x (cm)" and "y (cm)" seemed to break the reader. The reader works if "x" and "y" are used instead. We are looking into a fix for this problem.

Issues with EnSight. The current VisIt EnSight file format reader assumes that all "parts" have the same topological dimension (namely 3). The provided datasets had particles (dimension 0) which were causing the reader to fail. Offending line:
(In avtEnSightFileFormat::PopulateDatabaseMetaData())
avtEnSightFileFormat.C:748. mesh->topologicalDimension = 3;

Presentation by Arias, et al. at SIAM08, March 2008, Monterey CA

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