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We discuss the role of elastic stress in the statistical properties ofelastic turbulence, realized by the flow of a polymer solution between twodisks. The dynamics of the elastic stress are analogous to those of a smallscale fast dynamo in magnetohydrodynamics, and to those of the turbulentadvection of a passive scalar in the Batchelor regime. Both systems aretheoretically studied in literature, and this analogy is exploited to explainthe statistical properties, the flow structure, and the scaling observedexperimentally. Several features of elastic turbulence are confirmedexperimentally and presented in this paper: (i) saturation of the rms of thevorticity and of velocity gradients in the bulk, leading to the saturation ofthe elastic stress; (ii) large rms of the velocity gradients in the boundarylayer, linearly growth with Wi; (iii) skewed PDFs of the injected power, withexponential tails, which indicate intermittency; PDF of the accelerationexhibit well-pronounced exponential tails too; (iv) a new length scale, i.e thethickness of the boundary layer, as measured from the profile of the rms of thevelocity gradient, is found to be relevant and much smaller than the vesselsize; (v) the scaling of the structure functions of the vorticity, velocitygradients, and injected power is found to be the same as that of a passivescalar advected by an elastic turbulent velocity field.Comment: submitted to Physics of Fluids; 31 pages, 29 figures (resolution  reduced to screen quality

Elastic turbulence in von Karman swirling flow between two disks