1. Centro Interdipartimentale di Fluidodinamica e Idraulica, University of Udine, 33100 Udine, Italy
2. Institut Jean Le Rond D'Alembert, University Pierre et Marie Curie, 4 place Jussieu 75005 Paris, France
3. CNRS, UMR 7190 4 place Jussieu 75005 Paris, France
4. Department of Fluid Mechanics, CISM, 33100 Udine, Italy
5. Aerospace Engineering Department, University of Pisa, 56100 Pisa, Italy