RANS computations of a confined cavitating tip-leakage vortex

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Static axial induction control and tilt control are two strategies that have the potential to increase power production in wind farms, mitigating wake effects and increasing the available power for downstream turbines. In this study, wind tunnel experiment ...

The number of transient operations in hydraulic machinery connected to power grid, notably start-ups and shut-downs, has observed a substantial increase in recent decades, primarily driven by the global shift toward intermittent renewable energy sources. S ...

The global imperative to transition from fossil fuel-based energy sources to renewable alternatives has become increasingly urgent in the pursuit of sustainable and renewable power generation. This paradigm shift necessitates innovative approaches to manag ...

Large eddy simulations of tip vortex cavitation (TVC) around an elliptical hydrofoil is performed to study its scale effect. A satisfying agreement is obtained between the numerical and experimental data. It indicates that the scale effect of TVC is remark ...

Cavitation bubbles, extensively investigated in fluid mechanics, present enduring challenges in hydraulic machinery, while holding considerable potential for practical applications in biomedicine and sonochemistry. Despite more than a century of research, ...

According to the International Energy Agency, the global net-zero emissions objective requires the installed wind power capacity to increase 11-fold between 2020 and 2050. The scientific community has recently voiced concerns about the logistic feasibility ...

The presence of aerodynamic vortices is widespread in nature. They can be found at small scales near the wing tip of flying insects or at bigger scale in the form of hurricanes, cyclones or even galaxies. They are identified as coherent regions of high vor ...

The non-dimensional energy of starting vortex rings typically converges to values around 0.33 when they are created by a piston-cylinder or a bluff body translating at a constant speed. To explore the limits of the universality of this value and to analyse ...

Pulsatile jet propulsion is a highly energy-efficient swimming mode used by various species of aquatic animals that continues to inspire engineers of underwater vehicles. Here, we present a bio-inspired jet propulsor that combines the flexible hull of a je ...

Analytical wind turbine wake models are widely used to predict the wake velocity deficit. In these models, the wake growth rate is a key parameter specified mainly with empirical formulations. In this study, a new physics-based model is proposed and valida ...

This paper presents preliminary results of an experimental study on the occurrence and development of the upper part-load instability in a reduced-scale Francis turbine. The study includes draft tube pressure measurements, high-speed flow visualization, an ...

Numerical simulation of tip vortex cavitation (TVC) remains a challenging task in a variety of applica-tions, such as axial turbines and pumps as well as marine propellers. Although it is well known that TVC is highly sensitive to gas content, be it dissol ...

The flow in a Francis turbine at full load is characterised by the development of an axial vortex rope in the draft tube. The vortex rope often promotes cavitation if the turbine is operated at a sufficiently low Thoma number. Furthermore, the vortex rope ...

Ring vortices are efficient at transporting fluid across long distances. They can be found in nature in various ways: they propel squids, inject blood in the heart, and entertain dolphins. These vortices are generally produced by ejecting a volume of fluid ...

Vortex rings are very efficient at transporting fluid on long distances and can generate large forces, either thrust or drag. These abilities are influenced by the vorticity distribution within the vortex. Previous work on vortices produced by piston-cylin ...

In the framework of the new feed-in-tariff system in Switzerland for Small Hydropower Plants (SHP), the aim of the SmallFLEX project, led by HES-SO Valais and performed in collaboration with EPFL, WSL, EAWAG, PVE, and FMV, is to show how SHP can provide wi ...

Nowadays, the importance of providing frequency stability to power systems with hydropower units is significantly increasing due to the growing proportion of volatile renewable energy sources. However, the provision of such services, as frequency containme ...

The hydropower sector has recently raised the interest in pump as turbine (PaT) that can be a valid trade-off between capital cost and performance in micro-scale installations. Nevertheless, the modest efficiency of PaTs often restricts their exploitation. ...

For the design optimization of the Pelton turbine, it is highly demanded to investigate the flow inside the turbine casing, which includes the water jet from the nozzles, the interaction between the jet and rotating runner, and the flow ejected from the bu ...

Hydrodynamic cavitation is one of the major phase change phenomena and occurs with a sudden decrease in the local static pressure within a fluid. With the emergence of microelectromechanical systems (MEMS), high-speed microfluidic devices have attracted co ...

RANS computations of a confined cavitating tip-leakage vortex

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Enhancing Wind Farm Performance through Axial Induction and Tilt Control: Insights from Wind Tunnel Experiments

On the prediction of the induced damage by the start-up sequence of Francis turbines: On operational resilience framework

Study of flexible operating conditions in variable-speed hydraulic turbines : advanced models and experimental validation

Numerical study on the scale effect of tip vortex cavitation induced by incoming velocities and scale ratios

The influence of the gas on the dynamics of cavitation bubbles

Dynamic stall characterisation and control for vertical-axis wind turbines

Growth, timing, & trajectory of vortices behind a rotating plate

Estimating the non-dimensional energy of vortex rings by modelling their roll-up

Lagrangian analysis of bio-inspired vortex ring formation

A physics-based model for wind turbine wake expansion in the atmospheric boundary layer

An experimental study on the upper part-load elliptical vortex instability in a Francis turbine

A new Euler-Lagrangian cavitation model for tip-vortex cavitation with the effect of non-condensable gas

Investigation of the Time Resolution Set Up Used to Compute the Full Load Vortex Rope in a Francis Turbine

Scaling of the translational velocity of vortex rings behind conical objects

Evolution of the vorticity distribution in vortex rings

Numerical simulations of Pelton turbine flow to predict large head variation influence

Optimal CAM Computation of Kaplan Turbines Accounting for Wear and Tear Originated by Frequency Control

Numerical investigation on the volute cutwater for pumps running in turbine mode

Application of particle-based numerical analysis to the practical design of Pelton turbine

Design and fabrication of a vigorous "cavitation-on-a-chip" device with a multiple microchannel configuration