Aims

Knowledge and understanding of fluvial processes with the aim of designing fluvial works

Main themes

- In-depth knowledge of open-channel hydraulics
- Introduction to free-surface transient flows and numerical hydraulics
- Introduction to morphodynamic flows and to fluvial morphology: sediment transport, density currents and debris flows

Content and teaching methods

- Introduction: field of application of Fluvial Hydraulics, types of rivers, basic elements in morphodynamics (2 hours) ;

- Complements in steady open-channel flows (5 hours)
* Flows in natural rivers: pseudo-uniform flow
* Flow in irregular geometry:
* Flow between a bottom outlet and a reservoir
* Changes in bed slope
* Changes in the channel width and obstacles: bridges and dam piers, Venturi channels, weirs, broad crested weir
* Flow in rivers with floodplains

- Transient free-surface flows (10 hours)
* Shallow-water equations (Saint-Venant), analysis and solution using the characteristics
* Positive and negative waves
* Numerical methods: finite-differences, finite volumes, finite elements, shock capturing methods
* Models for fast or sudden transient flows: flash floods and dam-break flows ; introduction to turbulence modelling
* Extension to 2D models (horizontal plane)

- Sedimentology (12 hours)
* Definitions, general river morphology, bed forms and Exner equation
* Modes of grain transport and vertical structure of flows : types of sediment transport: suspension, collisional and frictional granular contacts, Bagnold's theory for dispersive stresses, types of sediment transport: density currents, dry granular flows, debris flow, fluvial flow: bed load, saltation and suspension ;
* Non-dimensional variables in sedimentology : velocity distribution, mean velocity and friction velocity, non-dimensional analysis and characteristic numbers ;
* Erosion limit of sediment beds: critical velocity criterion: equilibrium profile of a river, critical shear stress criterion: Shields' and van Rijn's diagrams ;
* Bed friction of alluvial rivers and stage-discharge relation: Eisntein's analysis
* Bed load transport:
du Boys principle, Meyer-Peter-Müller analysis, other common approaches (Einstein, Bagnold, etc.) ;
* Suspension transport:
transport equations, concentration distribution (Vanoni-Rouse theory), suspension load (Einstein's integration) ;

- Morphological evolution of rivers (10 hours)
* Sedimentological equilibrium of a river: practical formulae: sedimentological regime, bank resistance to erosion, profile of equally distributed resistance to erosion ;
* Morphological response to fluvial works: feeding by local sediment supply, local widening and constrictions, canalisation and clear water derivation, influence of a tributaries, local erosion: bridge piers, downstream side of weirs ;
* Principles of river training: secondary helical currents, Fargue's laws and rules, local works: surface panels, bandalls, bottom panels, amelioration of weirs and bends, bank protection, river training: principles of Fargue and Girardon ;
* Numerical models in fluvial morphology: notion of non-equilibrium and transport models, morphological models in equilibrium and non-equilibrium: equilibrium profile, nick point, dam-break on mobile bed ;

- Other modes of sediment transport in fluvial and torrential hydraulics (6 hours)
* Density and turbidity currents
* Debris flows: avalanches and torrential lava flows
* Transport of pollutants in rivers: mixing mechanisms and turbulent flows, vertical and transversal diffusion, longitudinal dispersion

Other information (prerequisite, evaluation (assessment methods), course materials recommended readings, ...)

- Complementary topic of the theme "Hydraulics"
- Prerequisite: AMCO 2152 "Hydraulics"
- Pedagogy: mix of lectures, practical and lab work-
- Evaluation: Exercise examination at the end of the semester (20% of total); transient flow computer programme during the year (20% of total); oral examination (60% of total)
- Support: syllabus

Other credits in programs