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Using a File Format that Loads CFD Data 10 Times Faster

The Challenge

Jared Gudenkauf is a CFD engineer (Jacobs engineering contractor) working in the fluid dynamics branch (ER42) of NASA Marshall Space Flight center in Huntsville, Alabama. Jared runs CFD in support of the Space Launch System (SLS), Mars Ascent Vehicle, and “Lunar Flashlight” Lunar Orbiter. His calculations for the SLS Ignition Over-Pressure/Sound Suppression water system involve two-phase flows.

Jared’s main CFD code is Loci/CHEM, which he runs on the Pleiades supercomputer at the NASA Advanced Supercomputing (NAS) center in California.

To generate his grid he uses AFLR3D from Mississippi State or Pointwise from Pointwise Inc. His grids are currently around 20 million cells in size, but he will be running 300 million cell cases soon.

To view his results, Jared uses the Loci/CHEM extract utility to generate a *.szplt (SZL) file, downloads it to his local system, and visualizes the results in Tecplot 360. Alternately, he may run Tecplot 360 in batch mode on the NAS system and download the resulting images.

The Solution

Before the SZL output option was added to the extract utility in Loci/CHEM, Jared would extract Ensight format files, load them into Tecplot 360, and visualize the results using iso-surfaces and slices through the plume. A data set would take from 10 to 15 minutes to load in the Ensight format. And the 64GB Linux workstation loading the Ensight data would sometimes run out of memory.

Jared now uses the SZL option that was recently added in the Loci/CHEM extract utility. He says that loading data in SZL file format is so much faster – it’s “like night and day” – and takes only a minute to load. It also uses much less memory, and let’s Jacob visualize the results on his 8GB Mac.
Jarad now almost exclusively uses Tecplot SZL format.

Tecplot has 10x less time to get to the first picture and more flexibility [than competitive postprocessors]. The fast loading times are amazing…it’s like night and day.

–Jared Gudenkauf, Jacobs contractor for NASA Marshall Space Flight Center

When asked what he meant by flexibility, he said its easier to “write out extracted slices and read ASCII files for quickly creating line-plots, etc.” When working with SZL files, Jared says, “The fast loading times are amazing.”