Orszag-Tang Vortex

Orszag-Tang Vortex Simulation

Below are videos of the Orszag-Tang Vortex simulation I ran with Cholla in late 2023. I ran the problem with the initial conditions detailed in Gardiner & Stone 2008 and at 19,278 voxels on a side; the maximum size that could be run in 3D on Frontier. The thickness was only a handful of voxels since every Z slice in this problem is identical and I didn’t want to waste a lot of computing power. As it stands, this simulation took about 12 hours to run on 25 GPUs and produced about 36TB of raw data. Nearly all the execution time was spent in I/O since I needed to output at a very high cadence to make videos like the ones below. The reduced data required for these videos is about 6TB and took ~750 CPU hours to animate.

Each video goes through the entire simulation time from initial to final state then slowly zoom in until you can see individual voxels, a comparison to indicate scale is at the end.

Density

X Component of the Momentum

Y Component of the Momentum

Energy

X Component of the Magnetic Field

Y Component of the Magnetic Field

Zoom Comparison

The image below shows the region covered by the final, most zoomed in, state of the visualization and has the voxels outlined. Note that there is a box to indicate the area of the zoomed image in the full image but that it is smaller than a single pixel.