Evidence of fractional transport in point-vortex flow
Résumé
Advection properties of passive particles in flows generated by point vortices are considered. Transport properties are anomalous with characteristic transport exponent $\\mu \\sim 1.5$. This behavior is linked back to the presence of coherent fractal structures within the flow. A fractional kinetic analysis allows to link the characteristic transport exponent $\\mu $ to the trapping time exponent $\\gamma =1+\\mu $. The quantitative agreement is found for different systems of vortices investigated and a clear signature is obtained of the fractional nature of transport in these flows.