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Cycle: 
22 cycle
Tutor: 
Prof. Vincenzo Armenio
Advisor: 
Prof. F. Ballio, Politecnico di Milano
Curriculum, Annual Report, Thesis: 
Current Position: 

Postdoctoral Research Scholar at IIHR-Hydroscience & Engineering, the University of Iowa, IA, USA (filippo-bressan@uiowa.edu)

Scientific Activity: 

The incipient of sediment motion in local scour phenomena remains an open problem in river hydraulics. The fundamental issue relies in the lack of understanding which are the length/time scales of turbulence that mainly affect the entrainment of particles. A numerical experiment was conducted in order to detect the principal turbulent structures developing around a 45° wing-wall abutment and to understand their role for the sediment entrainment. Different scour conditions were considered and the bathymetry was taken from experimental data available at the Politecnico di Milano. A Large Eddy Simulation code developed by Prof. Armenio in the past was used to compute the instantaneous three-dimensional flow field. Results clarified that simple eddy-viscosity closure models commonly adopted in Reynolds-Averaged Navier-Stokes modeling approach are not suited to simulate this type of problems. The coherent structures inside the scour-hole together with their bimodal fluctuations were found to affect the sediment motion patterns and they prevail over the typical bursting process of an undisturbed turbulent boundary layer to set the particles in motion.

Publications: 
  • Bressan F., Ballio F. and Armenio V. 2011 Turbulence around a scoured bridge abutment. Journal of Turbulence, Vol. 12(3), 1-24
  • Bressan F., Armenio V. and Ballio F. On the complexity of local scour processes. In progress for submitting to Journal of Hydraulic Engineering
Conferences: 
  • Bressan F., Ballio F. and Armenio V. LES of turbulence around a scoured bridge abutment. Journal paper: Proceedings of Direct and Large Eddy Simulation Workshop 8, July 7 - 9 July 2010, Eindhoven, The Netherlands. (Peer-reviewed conference paper)
  • Ballio F., Bressan F. and Armenio V. Resolved LES solutions for local scour modelling. Abstract: Proceedings of the XVIII International Conference on Water Resources CMWR 2010, June 21 24 2010, Barcelona, Spain. (Conference contribution)
  • Bressan F., Ballio F. and Armenio V. Turbulent flow field around a 45° wing-wall bridge abutment in different scour conditions. Proceedings of the first conference of IAHR Europe, May 4 - 6 2010, Edinburgh, UK. (Peer-reviewed conference paper)
  • Bressan F., Ballio F. and Armenio V. LES of the flow field around a 45° wing-wall abutment in different scour conditions. Bulletin of the American Physical Society 53(15), 2008. (Conference contribution)