The above movie is a visualization of a low Mach number gas kinetic simulation discretized with the D2Q9 Lattice Boltzmann Method solver (see LBM wiki). The domain was specified by an input PNG image.
Technical details: the simulation code is available from github here. The code is accelerated using OCCA. The above movie consists of 2400 frames, output once every one hundred time steps. It took a few minutes to compute on a single NVIDIA GTX 1080 TI using the OCCA CUDA backend and single precision (FP32) arithmetic.
Note: the above movie was made by stitching together the output PNG format image files with ffmpeg.