Publications de Michael Pfister

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Large wood (LW) elements are often transported by rivers into reservoirs during heavy rainfall events. Large wood has important environmental attributes that benefit the diversification of riverine ecosystems. There are several studies dealing with the tra ...

A comparative analysis of a wide range of air-water flow properties was conducted for two types of phase-detection intrusive probes including fiber-optical and conductivity probes. Experiments were conducted on a stepped spillway model for a skimming flow ...

Physical modeling represents probably the oldest design tool in hydraulic engineering together with analytical approaches. In free surface flows, the similitude based upon a Froude similarity allows for a correct representation of the dominant forces, name ...

Accumulations of floating debris in reservoirs can have negative impacts on the safe operation of a dam. Thus, adequate spillway design in view of driftwood is of paramount importance. Herein, investigation of driftwood blockage with a reservoir flow appro ...

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 ...

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 ...

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 ...

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 ...

The chute aerator of a spillway is a structure in such a sense that air is, in the intense emulsification, entrained into the high-velocity water flow. Correctly predicting the air entrainment and two-phase flow pattern at the aerator would contribute to r ...

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 ...

Hydrodynamic waves are an unsteady flow motion generated by rapid water level rise. In nature, such events can be found in dam-break waves, impulse waves and tsunamis. These phenomena are rare, but highly destructive. The present study is based on an exper ...

As an alternative to ski jumps, deflectors can be implemented on spillways to generate free jets. They guide, up to a certain limit, the jet to an achieved location onto the plunge pool surface, and furthermore enhance the process of jet disintegration. Th ...

Free overfall weirs are hydraulically efficient and reliable in operation. With this, the overfall capacity depends on the hydraulically active developed length of the weir. Folded types of weir, such as the piano key weir (PKW), provide an over-proportion ...

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 ...

One of the common measures for river bank protection is the installation of riprap. There are several methods to design riprap appropriately, which are however generally limited to dumped medium size blocks. Nevertheless, an additional resistance against e ...

Several stepped spillways have been built in recent decades, mostly integrated in the downstream faces of roller compacted concrete dams. Among them, only a few have changing bottom slopes. Comprehensive information on the effect of a slope change on the f ...

The collection of floating woody debris at flow control structures, such as spillways and weirs, can potentially result in reduced discharge efficiency (higher upstream head for a given weir discharge). Compared to less hydraulically-efficient control stru ...

Spillways are designed to evacuate floods in a safe way. They should safely release water in order to avoid dam overtopping with its related damages. Nevertheless, it may be dangerous to assume that a flood is only carrying “clear” water. Large woody debri ...

Waves impacting against structures can create damages and devastation. This topic regained interest after some recent catastrophic events and the present paper investigates the main phases of a wave impacting against a residential house commonly observed i ...

Numerous stepped spillways were built to date, namely on RCC gravity dams or on valley flanks besides embankment or rockfill dams, while some others are currently under design or construction. In some cases, slope changes may be required on stepped chutes, ...

Michael Pfister

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Spillway blockage caused by large wood in reservoirs

Comparative analyses of phase-detective intrusive probes in high-velocity air-water flows

Two-phase air-water flows: Scale effects in physical modelling

Blockage of driftwood and resulting head increase upstream of an ogee spillway with piers

Wave-reducing Stern Flap on Ship Convoys to Protect Riverbanks

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

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

Reservoir Level Rise under Extreme Driftwood Blockage at Ogee Crest

Studies of Two-Phase Flow at a Chute Aerator with Experiments and CFD Modelling

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

Velocity profile measurements in bore waves

Air concentration distribution in deflector-jets

Das Klaviertastenwehr (PKW) als effizientes Einlaufbauwerk zur Erhöhung der Abflusskapazität bestehender Hochwasserentlastungsanlagen

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

Effect of compressed riprap thickness on the stability of river banks

Effect of an abrupt slope change on air entrainment and flow depths at stepped spillways

Debris-Blocking Sensitivity of Piano Key Weirs under Reservoir-Type Approach Flow

BLOCKING PROBABILITY OF DRIFTWOOD AT OGEE CREST SPILLWAYS WITH PIERS: INFLUENCE OF WOODY DEBRIS CHARACTERISTICS

Example of wave impact on a residential house

Air entrainment and pressure development in skimming flow on an abrupt slope change on stepped spillways