Publications de Giovanni De Cesare

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Since the adoption of the "Energy Strategy 2050" by the Federal Council in 2017, Switzerland has been looking for new energy alternatives to the nuclear sector and ways to reduce its greenhouse gas emissions, in particular by promoting the development of renewable energies. The national hydroelectric park, which represents 59% of total energy production, has an essential place in this context of upheaval in electricity supply. In the coming years, more and more existing power plants will come to the end of

In the framework of a research project studying the influences of pumping/turbine modes on turbulence, flow fields and suspended sediments in reservoirs, prototype measurements are carried out at the Grimsel II pumped storage plant (Switzerland). In situ recordings comprise flow and velocity patterns in the lower reservoir. For the measurement of flow velocities, Acoustic Doppler Current Profiler (ADCP) devices have been fixed on the reservoir bottom in front of the intake/outlet structure. The temporal evo

Flood protection often calls on to the realization of retention works for bed load as well as wood and debris flow. Certain relatively recent arrangements did not perform according to their intended function, what shows the complexity of the design and the ...

The performance of circular and linear jet arrangements on the release of suspended sediment out of a prismatic tank has been investigated. Experiments conducted are (1) without any forced jet stirring (reference case), (2) four jets arranged in a horizont ...

Long-term sedimentation of pumped storage reservoirs due to the alternation of turbine and pumping modes is an issue regarding sustainability and reliability of such schemes. Systematic experiments on a cuboidal basin are conducted to study how flow fields, turbulence and settling down of fine sediments are affected by discharge, duration of pumped storage sequences, sediment concentration and intake/outlet location. The experimental setup allows simulating inflowing jet into a reservoir, as well as water e

The loss of biodiversity in freshwater environments is becoming an increasing problem globally. As a result, many tools have been developed and improved to reduce this decline. However, there is still a need for the identification and evaluation of precise ...

The deposition of fine sediment on top of the riverbed affects the reproduction of spawning fishes and some species of benthos. The clogging of the substrate resulting from this deposition is a well-known issue in rivers affected by anthropogenic activity ...

Throttle surge tanks are a part of high head powerplants. The main consequence of a throttle placement is to introduce head losses by accelerating the flow. They make it possible to manage extreme water levels during mass oscillations while increasing water surge, e.g. water hammer, in the headrace tunnel. This phenomenon happens every time the flow discharge is changed in the waterway. Either throttle is placed during construction to reduce costs or its placement is needed following a refurbishment to adap

Spillways are a requirement for dams’ safety, mainly preventing overtopping during floods. A common spillway solution involves plunging jets, which dissipate a considerable flow energy in the plunge pool. Energy dissipation has to occur in a controlled man ...

The Duge pumped storage power plant in Norway currently experiences a problem with rotor-lifting. One of the two vertical 100 MW units lifts up off its bearings when operated above a certain load. The vertical forces on the units have been known to be marginally balanced, but the problem increased when the turbines, commissioned in 1979, were refurbished in 2017. One of the reasons is the significant submergence of the units combined with a 12 km long tailrace tunnel, which produces significant friction los

Inland navigable waterways are significant in cargo transport and leisure activities. In parallel, these channels and rivers often suffer from the ship traffic, as the generated waves may damage waterway banks, along with their riparian fauna. As a consequ ...

As revitalization and protection against floods are essential in our time, the town of Delémont in Switzerland has set up a major project named “Delémont Marée Basse”. Part of the project, the residual risk plans to be managed by a lateral overflow bypassi ...

Pump and turbine operations lead to head losses in the tailrace channel. Pumping discharge may be limited due to potential air entrainment into the pump shaft when the downstream reservoir is at its lowest level and the head losses are high. Regarding turbine operations, the limit is given by the maximum level in the Pelton turbine chamber due to high water level in the downstream reservoir and head losses. For the extended Hongrin-Léman pumped-storage scheme in Switzerland, the rapid operations of turbines

Impaired sediment transport can have numerous adverse impacts on the eco-morphodynamics of the riverscape. If well designed, sediment augmentation measures present a promising mitigation approach at different scales. This chapter focuses on flume experim ...

Bridge failure, due to local scour at bridge pier foundations, has become a critical issue in river and bridge engineering, which might lead to transportation disruption, loss of lives and economic problems. A practical solution to prevent bridge collapses ...

Sediment management of alpine rivers is crucial to ensure sustainable hydropower production. Dams inhibit not only biological consistency but also drastically restrain natural sediment dynamics. Upstream of the dam, coarse material is accumulated, leading to a progressive sedimentation of the reservoir. This causes a reduction in the effective water head and can even lead to the blockage of lowerlying operation organs. Downstream of the dam, reduced flow velocities promote the settling of suspended sediment

A part of the domestic waste of the city of Geneva (Switzerland) is transported with ship convoys on the Rhone River to the waste incineration station. These convoys generate waves, which partially endangers the stability of the river banks and the riparia ...

Geomembrane systems have been used in dams and reservoirs as rehabilitation technology since several decades and are now used worldwide. They act as impervious layer to prevent and mitigate water leakage and damage to structures. They meet the needs of man ...

Orifices are hydraulic devices producing pressure drops or head losses in pipes ways. Flow velocity measurements at the upstream of orifices allow understanding the effect of given flow field on head losses, while downstream measurements provide informatio ...

Sedimentation close to dams in large and deep reservoirs is mainly related to sediment transport by turbidity currents. The state of the art regarding the management of turbidity currents is presented here, and illustrated with two case studies. Possible solutions, such as the development of physical obstacles and the evacuation of sediments from water intake structures, are proposed.

Giovanni De Cesare

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Renewal of alpine hydroelectric plants according to the spatial and temporal scales of analysis

Influence of pumped storage operation on flow conditions near intake/outlet structures : in situ measurement using ADCP

Design of a bed load and driftwood filtering dam, analysis of the phenomena and hydraulic design

Release of suspension particles from a prismatic tank by multiple jet arrangements

Experiments on turbulence and settling down of fine sediments induced by pumped storage operations in a cuboidal reservoir

Ecological and biogeomorphological modelling of brown trout (Salmo trutta L.): Hints for improvements

Limits between surface and inner clogging of riverbed by fine sediment

Surge tank throttles for safe and flexible operation of storage plants

Plunging Circular Jets: Experimental Characterization of Dynamic Pressures Near the Stagnation Zone

Case study of rotor lifting in a pumped storage hydropower plant in Norway

Wave-reducing Stern Flap on Ship Convoys to Protect Riverbanks

Design of a diversion structure for the management of residual risks using physical model tests

Flow and waves in a common tailrace channel of two pump-storage plants - physical and numerical simulation

Sediment continuity and augmentation measures

Influence of collars on reduction in scour depth at two piers in a tandem configuration

Integrated sediment management of alpine rivers

Waves generated by ship convoy: Comparison of physical and numerical modeling with in-situ measurements

Dynamic behavior of exposed geomembrane systems in pressure waterways

Non-intrusive flow velocity measurements in pressurized pipe with orifice

Innovative approaches to sediment management