Visualization of Vortex Shedding with Particle Tracing

I've recently developed a software library for particle tracing for steady/unsteady flow fields on moving unstructured grids. Below is the visualization of vortex shedding behind a cylinder at Re=100. The velocity field was computed using my 2-D LSFEM code .

A longer (and larger) version of this animation is available here.
A 3-D version: