River Dynamics - 5EUS5DYF

Goal(s)

First part: fluvial dynamics.
Understand the physics and the modeling of unsteady flows in the rivers and canals (propagation of the tide, floods and of rapidly varying flows in the rivers and canals). Saint Venant equation formulation.
Design the volume of retention dams for flood protection.
Understanding the links between the physical reality, its perception and its modeling.
Brief presentation of the market software properties dealing with this problem.

Second part: sediment transport.
Students will become acquainted with the pluridisciplinary aspects of this topic.
Student will be asked to master: the concept and the quantitave determination of sediment mouvement inception, computation of sediment transport rates, the concept of sedimentary equilibrium (river bed slope, grain size distributions), engineering tools of the field

Content(s)

First part: fluvial dynamics.
1.- Introduction on the floods and floodings. Relinders on open channel hydraulics Hydraulics.
2.- One-dimensional free surface flows: the Barré de Saint-Venant PDE equations. Physical meaning of the different terms of the equations. Mathematical properties: the characteristics and the invariants.
3.- Physics of floods and their modeling. Kinematic and diffusive approximation. Example: the deterministic runoff.
4.- Flood alleviating structures: physical principles and optimisation of dams by a costs-benefits analysis
5.- Rapidly varying unsteady open channel flows dominates by inertia: shock and rarefaction waves. Sudden stop of a flow and dam breakage.

Second part: sediment transport.
1. Fundamental concepts: the various modes of sediment transport, the materials, introduction to river morphology.
2. Elementary analysis of the bed-load mechanism: threshold conditions of sediment movement, sensitivity of Meyer-Peter and Muller formula. The Einstein formula
3. 1D analysis of sediment transport: predictive formulaes and their range of applicability.
4. Deeper in the mechanisms of the sediment transport: transport in suspension, grain roughness, shape roughness, dune and bed forms, secondary currents, transported grain size distribution and bottom grain size distribution, grain size sorting by the flow, hiding effects & armoring.
5. Morphological changes

• Open channel hydraulics
• Fluid mechanics and turbulence
• Hyperbolic partial differential equations (characteristics)
• Statistics