The Kelvin-Helmholtz test problem is a standard test of hydrodynamical algorithms. In this problem, two volumes of fluid of uniform density (which may be different) are separated by a planar interface, and are given an initial relative velocity parallel to this interface. The interface is often given a small perturbation, and in a non-viscous fluid these perturbations rapidly develops into vortices due to the Kelvin-Helmholtz hydrodynamical instability. This can be a very useful test of Eulerian hydrodynamical codes (see, e.g., Robertson et al. 2010)
The movies found below were created using a 2D simulation of the Kelvin-Helmholtz test problem using version 2.4 of the Enzo code, and with this Enzo parameter file. The simulation is initialized on a 256x256 cell Cartesian root grid with two levels of adaptive mesh, with mesh refinement occurring based on the local velocity shear. Links to the movies on YouTube are provided, but you can also directly download mp4 versions of the movies (which are around 6-10 MB apiece) via the links below the embedded YouTube movies, as well as the yt scripts used to make the movie frames from the Enzo simulation data. These scripts assume that you are using version 2.6 of the yt code - if you are using version 3.x, some small modifications will be necessary (consult the yt documentation for details). Note that all of the movies cover exactly the same time span, and use the same framerate. Movies were generated from individual frames using the ffmpeg tool.
Attribution: if you choose to use any of the movies or images on this site, please use the attribution: "(c) Brian O'Shea (MSU) and the Enzo Collaboration, 2014"