  In a recent experiment, Kwon et. al (arXiv:1403.4658 [cond-mat.quant-gas])
generated a disordered state of quantum vortices by translating an oblate
Bose-Einstein condensate past a laser-induced obstacle and studying the
subsequent decay of vortex number. Using mean-field simulations of the
Gross-Pitaevskii equation, we shed light on the various stages of the observed
dynamics. We find that the flow of the superfluid past the obstacle leads
initially to the formation of a classical-like wake, which later becomes
disordered. Following removal of the obstacle, the vortex number decays due to
vortices annihilating and reaching the boundary. Our results are in excellent
agreement with the experimental observations. Furthermore, we probe thermal
effects through phenomenological dissipation.
