Numerical simulations of experiments on quasi-two-dimensional turbulence

We report direct numerical simulations (DNS) of the two-dimensional (2D) Navier-Stokes equation, including a linear friction term which parallels a series of recent experiments on decaying quasi-2D turbulence in thin, stably stratified, fluid layers. If we start the DNS from the experimental situation when transient processes within the layers have died away, then quantitative comparison between simulation and experiment shows a remarkable agreement for the temporal evolution of the stream function and the vorticity field. The results confirm the two dimensionality of the experimental dynamics after a short initial period of relaxation and suggest the use of 2D simulations for extrapolating the observations to the case without bottom friction, inaccessible to experiments with stratified fluids.