  Elastic turbulence is a chaotic regime that emerges in polymer solutions at
low Reynolds numbers. A common way to ensure stability in numerical simulations
of polymer solutions is to add artificially large polymer-stress diffusion. In
order to assess the accuracy of this approach in the elastic-turbulence regime,
we compare numerical simulations of the two-dimensional Oldroyd-B and FENE-P
models sustained by a cellular force with and without artificial diffusion. We
find that artificial diffusion can have a dramatic effect even on the
large-scale properties of the flow and we show some of the spurious phenomena
that may arise when artificial diffusion is used.
