This instability arises when the interface between two fluids in shear motion is perturbed, and for this problem the body forces, and , are zero. In these figures, the density of the massless marker particles normalized by the fluid density is plotted on a color map, with red corresponding to a density of one through green, blue, and white to a density of zero.
Vortices form along the interface and interact before being lost to numerical diffusion.
By processing the output from the nCUBE-1, a videotape of the evolution of the instability was produced. This sample problem demonstrates that the FCT technique is able to track the physical instability without introducing numerical instability.