Publications by Michael Pfister

Effect of blocked driftwood on the hydraulic performance of a gated standard weir

Giovanni De Cesare, Michael Pfister, Loïc Bénet

Driftwood belongs to riverine ecosystems and is stored and transported in every natural stream. Hydraulic structures built in streams typically alter the flow characteristics and might consequently get in conflict with driftwood. The latter can get trapped ...

International Association for Hydro-Environment Engineering and Research (IAHR)2022

Performance and Design of a Stepped Spillway Aerator

Anton Schleiss, Stéphane Christian Olivier Terrier, Michael Pfister

Stepped spillways are frequently limited to specific discharges under around 30 m2/s due to concerns about potential cavitation damages. A small air concentration can prevent such damages and the design of bottom aerators is well established for smooth chu ...

2022

Bottom-Pressure Development Due to an Abrupt Slope Reduction at Stepped Spillways

Anton Schleiss, José Pedro Gamito de Saldanha Calado Matos, Michael Pfister, Mohammad Javad Ostad Mirza

Fluctuating bottom-pressures on stepped chutes are relevant for the spillway design. An abrupt slope reduction causes a local alteration of the bottom-pressure development. Little information is available regarding the air–water flow properties near an abr ...

2022

Force imposée sur un râtelier en amont d’un évacuateur de crue par des bois flottants, et concept pour favoriser le passage des bois flottants

Giovanni De Cesare, Michael Pfister, Loïc Bénet

L’obstruction de l’évacuateur de crue d’un barrage par des bois flottants peut réduire sa capacité hydraulique. Pour limiter cet effet, un râtelier peut être installé pour retenir les bois en amont de la section critique d’écoulement. Sur la base d’une mod ...

2022

Blockage Probability Modeling of Large Wood at Reservoir Spillways With Piers

Anton Schleiss, José Pedro Gamito de Saldanha Calado Matos, Michael Pfister, Paloma Furlan

Large wood increases the morphological and hydraulic complexity of rivers, yet it may block and modify the flood discharge capacity of hydraulic structures. To assess the related risk, blockage probability estimation for hydraulic structures such as reserv ...

2021

Reservoir Level Rise under Extreme Driftwood Blockage at Ogee Crest

Giovanni De Cesare, Michael Pfister, Loïc Bénet

Dams are civil structures essential to modern civilization. However, they can be a threat if not properly designed and operated. A particular risk that potentially can lead to dam failure is the blocking of the spillway inlet with driftwood or debris. This ...

2021

Closure to "Reservoir Level Rise under Extreme Driftwood Blockage at Ogee Crest" by Loic Benet, Giovanni De Cesare, and Michael Pfister

Giovanni De Cesare, Michael Pfister

2021

Statistical accuracy for estimations of large wood blockage in a reservoir environment

Anton Schleiss, José Pedro Gamito de Saldanha Calado Matos, Michael Pfister, Paloma Furlan

The blockage of weirs or bridges by in-stream wood can reduce the flood discharge capacity, leading to hazardous situations. To assess the related risk, blocking probabilities quantifications are needed. However, large wood has a random behaviour and it is ...

SPRINGER2020

Hydraulic design of classical stilling basins downstream of stepped chutes

Giovanni De Cesare, Anton Schleiss, José Pedro Gamito de Saldanha Calado Matos, Michael Pfister, Ivan Stojnic

New design information regarding the hydraulic behaviour of classical stilling basins downstream of stepped chutes is presented and discussed. An extensive experimental campaign revealed that classical stilling basins preceded by stepped chutes cannot be a ...

2020

Bottom pressure characteristics in a stilling basin downstream of a stepped spillway for two different chute slopes

Anton Schleiss, José Pedro Gamito de Saldanha Calado Matos, Michael Pfister, Ivan Stojnic

In the last decades numerous stepped spillways were built, mostly on the downstream face of roller compacted concrete (RCC) dams. Stilling basins are often used as an energy dissipater. Although the hydraulics of stepped chutes was extensively investigated ...

The University of Queensland2020

Impact hydrodynamique des vagues contre les bâtiments

Anton Schleiss, Michael Pfister, Davide Wüthrich

Les tsunamis, les vagues d'impulsion et les ruptures de barrages représentent des phénomènes extrêmes qui mettent en danger la vie des personnes et la fonctionnalité des infrastructures. Des événements récents dans l'Océan Indien (2004), au Japon (2011) et ...

2020

Effet des bois flottants obstruant un évacuateur de crue dans des conditions extrêmes

Giovanni De Cesare, Michael Pfister, Loïc Bénet

Le transport de bois flottants peut induire des obstructions aux ouvrages hydrauliques et limiter leurs fonctionnalités et leurs capacités de décharge. Le blocage de l’entrée d’un évacuateur de crue d’un barrage par des bois flottants représente un risque ...

2020

Forces on buildings with openings and orientation in a steady post-tsunami free-surface flow

Anton Schleiss, Michael Pfister, Davide Wüthrich

Steady free-surface flows around buildings occurring during flood or tsunami events can produce major damages and a quantification of the post-peak forces is essential for safety and resilience of coastal structures. The loading process is highly affected ...

2020

Effect of 30-Degree Sloping Smooth and Stepped Chute Approach Flow on the Performance of a Classical Stilling Basin

Anton Schleiss, José Pedro Gamito de Saldanha Calado Matos, Michael Pfister, Ivan Stojnic

Advances in dam construction techniques have significantly increased the number of stepped spillways implemented worldwide. Although stepped chutes provide enhanced energy dissipation along the chute, as compared to smooth chutes, an adequate energy dissip ...

2020

Effect of debris damming on wave-induced hydrodynamic loads against free-standing buildings with openings

Anton Schleiss, Michael Pfister, Davide Wüthrich, Claudia Ylla Arbos

Tsunamis, impulse waves, and dam-break waves are rare but catastrophic events, associated with casualties and damage to infrastructures. An adequate description of these waves is vital to assure human safety and to generate resilient structures. Furthermor ...

2020

Bemessung von klassischen Tosbecken unterhalb von Treppenschussrinnen

Giovanni De Cesare, Anton Schleiss, José Pedro Gamito de Saldanha Calado Matos, Michael Pfister, Ivan Stojnic

Aufgrund des Fortschritts im Talsperrenbau mit Walzbeton (RCC) werden weltweit häufig Treppenschussrinnen erstellt. Nach jeder Schussrinne ist ein hydraulisches Bauwerk zur Energiedissipation vorzusehen, beispielsweise ein Tosbecken. Obwohl die Hydraulik v ...

2020

Effect of a second layer on the time to failure of compressed riprap as mountain riverbank protection

Anton Schleiss, Mário Jorge Rodrigues Pereira Da Franca, Mona Jafarnejad Chaghooshi, Michael Pfister

Recently, Jafarnejad, Franca, Pfister, and Schleiss [2017. Time-based failure analysis of compressed riverbank riprap. Journal of Hydraulic Research, 55(2), 224–235. doi: 10.1080/00221686.2016.1212940] presented an experimental study on the stability of co ...

Taylor & Francis Ltd2019

Effect of building overtopping on induced loads during extreme hydrodynamic events

Anton Schleiss, Michael Pfister, Davide Wüthrich, Ioan Nistor

Tsunamis, impulse-waves and dam-break waves have affected humanity in recent decades and the construction of vertical shelters can provide safety to people. However, for non-critical infrastructures, typically residential houses of lower height, overtoppin ...

Taylor & Francis Ltd2019

Experimental and numerical study on wave-impact on buildings

Giovanni De Cesare, Michael Pfister, Davide Wüthrich, Shun Nomura

Unsteady flows such as tsunamis, impulse waves and dam-break waves can lead to damages and human losses. Hence, specific research to limit casualties and reconstruction costs is needed. The complexity of the phenomena involved suggests that a hybrid experi ...

2019

Upstream Erosion and Sediment Passage at Piano Key Weirs

Anton Schleiss, Michael Pfister, Ivan Stojnic

Piano key weirs (PKWs) are a weir type characterized by an effective rating curve. Accordingly, this control structure is primarily applied at dams to increase the spillway capacity. In recent years, PKWs also have been implemented in rivers combined with ...

2019