Themen der Lehrveranstaltung
- Module 1:
Hydraulics of open channel flows and transport processes in streams and rivers
1. Introduction
Review of basic hydraulic concepts: mass and momentum conservation (integral formulation), steady uniform flow in pipes, Bernoulli theorem.
Fundamental equations for open-channel flows: main concepts and assumptions in the derivation of the one-dimensional (cross section average) continuity and momentum equations (Saint Venant equations). Hierarchy of hydraulic models (from 3D local, instantaneous to 1D)
2. One-dimensional open channel flows
Flow resistance in turbulent flows; uniform flow model; channel design problem; stage-discharge curves in natural cross-sections.
Steady-state water surface profiles gradually varied flows: subcritical and supercritical flows; boundary conditions, locations and type. Specific energy; hydraulic jump. Gradually varied flows: effect of variable geometry and variable discharge.
Unsteady flows: flood waves, celerity of propagation, simplified models (kynematic model, parabolic model). Hysteresis in the stage-discharge rating curve. Hydropeaking waves.
Numerical models for the simulation of open channel flows (HEC-RAS software).
3. Fluvial hydraulics and eco-hydraulics
Basic concepts of river hydro-morphology. Sediment transport (bed load and suspended load); erosion and deposition processes. Implications for river morphological evolution.
Environmental effects of hydropower production on river systems. The national and international regulatory framework. Methods to calculate ecological flows. Hydrological methods and hydraulic-habitat methods. Hydropeaking and related effects.
- Module 2:
Hydrological modeling for hydropower systems and analysis of the elements of HPP
II-1 Introduction (4 hours).
Principles of functioning of a Hydro power plant; classification and main components of a HPP. Pumped-storage HPPs. Hydrological curves, duration curves and their use for a reservoir or a RoR HPP design.
II-2 Basics of hydrology and hydrological modelling (8 hours)
The main components of the hydrological cycle; the water balance (continuity equation); precipitation; floods and droughts; the return time. The uses of water resources. Acquisition of hydro-meteorological data. The main processes of the hydrological modules that constitute an hydrological model. Models for evapotranspiration, plant interception and infiltration, snow-glacial dissolution, infiltration. Full models: the kinematic model. Continuous hydrological models. Construction criteria of a hydrological model at the basin scale. Calibration and validation of models.
II-3. Flow measurement (4 hours)
Weirs, the method of area-velocity, the dilution method, measurement errors, and its influence on the flow rate scales.
II-4. Plant design (34 hours)
Hydroelectric plants with reservoir and run of the river plants (RoR), operations management for hydroelectric plants. Analysis of the functional elements constituting a hydroelectric plant: barrages and intakes (dams, sedimentation channels); headraces, channels and adduction tunnels; surge tanks; penstocks; turbines; alternators; regulators; tailrace.
Classroom exercises: filtration under dams and dikes; Global stability of dams and dikes; siphoning; drainage of excavations. One exercise among: analysis of water hammer in a pressure pipe, mass oscillation analysis in a surge tank, Reservoir volume and production design.
Unterrichtsform
The theory is presented by means of lectures in class. Examples of exercises supporting the theoretical aspects are proposed by the lecturers during teaching hours. Further analyses, which include the solution of various types of exercises and problems, are left to the autonomous study of the students.
Observation of key open channel flow processes in the hydraulic laboratory is used to increase concept understanding. A one-day field visit to hydropower plants is usually organized within the course.