Ph.D. assistantship available in Discrete element modeling of bedload sediment transport (Grenoble, France)
Ph.D. position available in bedload sediment transport modeling
The National Research Institute of Science and Technology for
Environment and Agriculture (IRSTEA, Centre de Grenoble),
invites applicants for a three year Ph.D. assistantship begining in
September 2012. The researcher will work on bedload sediment transport modeling based on Discrete Element method.
Transport of bedload, the larger material that is transported in stream channels, has major consequences for public safety, for the management of water resources, and for environmental sustainability. In particular, in mountains, steep slopes drive intense transport of a wide range of grain sizes. As discussed recently (Frey and Church, 2009), an important reason for our limited ability to predict sediment flux is that we have no general understanding of grain-grain interactions in stream channels, especially due to a very wide range of grain size leading to grain size sorting or segregation. Movement of beads on a mobile bed in a turbulent supercritical flow on steep slopes has been studied at Cemagref in a two-dimensional channel. A high speed camera and image analysis allow us to measure variables at the particle scale such as positions, instantaneous velocities, trajectories, states of movements. Two datasets are available, one relative to a uniform size of particle, the other pertaining to a segregating binary mixture.
This PhD subject is about discrete element modelling of bedload. In this type of modelling, each individual particle (sand grain, rock, etc.) is taken into account and intergranular interactions are modelled with simple laws (e.g. Coulomb friction). Gravity and contact forces permit to solve the dynamical behaviour of the system. The main issue will be to couple an existing discrete element model (yade-dem.org) with the fluid, taking into account hydrodynamic forces. Calibration and validation will be performed with the help of both the uniform and binary datasets. Ideal candidates will have:
- excellent academic background; - a strong background in a scientific field related to Mechanics (fluid, solid or soil), Physics (granular, media or fluids), Applied mathematics;
- a strong interest in numerical modelling; - computer programming experience (C++, Python); - good level of English; - basic command of French (desirable);
IRSTEA (ex-Cemagref) is a public research organisation depending on the Department of Agriculture and the Department of Research of the French Government. It employs over 1000 scientists and technicians specializing in interdisciplinary research in the field of environmental sciences, natural risks, rural life, agriculture, soil conservation, water quality, vegetation and wildlife. The Grenoble centre is specialized in mountain-related issues. It conducts research in analysis and modelling of physical processes involved in the initiation and flowing of bedload transport, debris flows and snow avalanches, and their interactions with protective structures. Further inquiries:
For more information please contact to Philippe Frey ([hidden email]) before 1 May 2012.