Alireza Khoshkonesh - Ph.D. in hydraulics, water structures, department of water engineering, Bu-Ali Sina university, Hamedan ۶۵۱۷۸, (Islamic republic of Iran)
Fariba Ahmadi Dehrashid - Ph.D. student in hydraulics, water structures, department of water engineering, Bu-Ali Sina university, Hamedan ۶۵۱۷۸, (Islamic republic of Iran)Email: faribaahmadi۹۱@gmail.com
Blaise NSOM - Université de Bretagne Occidentale. IRDL/UBO UMR CNRS ۶۰۲۷. Rue de Kergoat, ۲۹۲۸۵ Brest, France
Saeed Gohari - Assistant professor of hydraulics structures, Department of Water Engineering, Faculty of Agri-culture, Bu-Ali Sina University, Hamedan, ۶۵۱۷۸, (Islamic republic of Iran)
Hossein Banejad - Associate professor of hydraulics, department of water engineering, college of agriculture, Fer-dowsi university of Mashhad, Mashhad, ۹۱۷۳۵ (Islamic republic of Iran
Payam Heidarian - MSc in water and hydraulic structures engineering, Department of hydraulic structures, Faculty of civil and environment engineering, Tarbiat Modares University, Iran

In this paper, the effect of the sediment bed elevation on dam-break flow over mobile beds is scrutinized using the volume of fluid (VOF) method. While the equations of motion are tackled employing the finite-volume and standard k-ε turbulence closure model. The morphological characteristics are studied using the van Rijn bed load transport model. The results show that an increase in the downstream bed elevation leads to reducing: a) the flow advancing distance and water rising over the end wall, b) the sediment transport rate downstream and c) the reservoir releasing rate. It causes the formation and evolution of two hydraulic jumps and corresponding scour holes in the near field and the downstream channel.

Dam-break, Mobile-bed, Bed elevation, k-ε, RANS, VOF.