BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Memento EPFL//
BEGIN:VEVENT
SUMMARY:On the influence of coherent structures on flow hydrodynamics\, tr
 ansport and mixing at river confluences
DTSTART:20150922T120000
DTEND:20150922T131500
DTSTAMP:20260924T071723Z
UID:1198b828c146dbca0551af5266bdf02b46f084a2c436431405896f3c
CATEGORIES:Conferences - Seminars
DESCRIPTION:Dr Georges Constantinescu\, IIHR-Hydroscience & Engineering\, 
 Civil and Environmental Engineering Dept\, The University of Iowa\, USA\nA
 bstract:\nRiver confluences are fundamental components of river networks t
 hat play an important role in regulating the movement of sediment through 
 these networks and are habitats of high ecological value. The convergence 
 of flow induced by the configuration\, or planform\, of the two conjoining
  channels results in highly three-dimensional patterns of fluid motion. Dy
 namics of mixing controls how tributary inputs of nutrients and food are d
 ispersed in the main river\, downstream of the confluence.\nWe investigate
  flow structure and mixing based on Detached Eddy Simulations conducted fo
 r several natural river confluences with both a concordant bed and with a 
 high degree of bed discordance\, respectively. Additional information on t
 he effects of confluence angle\, bed roughness\, stratification and channe
 l curvature on the development of the shallow mixing interface (MI) and mi
 xing between the two streams is obtained from simulations conducted in mor
 e idealized geometries. We analyze the spatial development of the MI as a 
 function of the main geometrical and flow parameters defining the confluen
 ce and how bed friction affects the dynamics of the MI eddies. We also inv
 estigate the role played by the large-scale turbulence and\, in particular
 \, by the quasi-2D eddies generated within the MI and by the streamwise-or
 iented vortical (SOV) cells forming in the vicinity of the mixing interfac
 e in mixing and sediment entrainment at natural river confluences with a c
 oncordant bed.  Numerical results show that strongly coherent SOV cells a
 re one of the main mechanisms for the growth of the confluence scour hole.
  We show that the main reason why SOV cells have a large capacity to entra
 in sediment is because their cores are subject to large-scale bimodal osci
 llations toward and away of the mixing interface\, which greatly enhances 
 the erosion capacity of these structures.Short biography:\nDr. Constantine
 scu is a Professor in the Civil and Environmental Engineering Department a
 t the University of Iowa and a Research Engineer at IIHR-Hydroscience and 
 Engineering. Dr. Constantinescu got his Ph.D. at the University of Iowa in
  1998. Following this\, he occupied various research positions at Arizona 
 State University and at the Center for Turbulence Research and the Center 
 for Integrated Turbulence Simulations at Stanford University where he work
 ed on the development of novel numerical algorithms for viscous flows on s
 tructured and unstructured meshes\, Detached Eddy Simulation and computati
 onal aero-acoustics. He then joined the University of Iowa as an Assistant
  Professor in 2004. His research program is based on the use of eddy-resol
 ving simulations to understand the physics of several important classes of
  environmental and geo-physical flows. Dr. Constantinescu’s current rese
 arch focuses on applications related to river engineering\, flow and trans
 port processes around hydraulic structures\, stratified flows and fluid-st
 ructure interaction\, shallow flows\, eco-hydraulics and flow in porous me
 dia. Dr. Constantinescu has published over 70 journal papers and 150 confe
 rence papers.
LOCATION:GR A3 32 http://plan.epfl.ch/?room=GR%20A3%2032
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR