Publications associées à A model for the effect of pressure gradient on turbulent axisymmetric wakes

An improved analytical framework for flow prediction inside and downstream of wind farms

This study evaluates available analytical wake models for flow prediction inside and downstream of wind farms of different sizes and layouts using large-eddy simulation (LES), and introduces an enhanced analytical framework. All the tested analytical wake ...

Pergamon-Elsevier Science Ltd2024

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

Fernando Porté Agel, Guillem Armengol Barcos

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 ...

MDPI2024

Towards an improved understanding of wind turbine wakes in complex terrain

Arslan Salim Dar

In this thesis, we explored the effect of certain terrain-induced flow phenomena on the development of wind turbines sited in complex terrain. A combined experimental and analytical approach is used to study wind turbine wakes in different types of complex ...

EPFL2024

Wind turbine wake superposition under pressure gradient

Fernando Porté Agel, Arslan Salim Dar

We investigate the effect of pressure gradient on the cumulative wake of multiple turbines in wind tunnel experiments spanning across a range of adverse pressure gradient (APG), zero pressure gradient (ZPG), and favorable pressure gradient (FPG). Compared ...

2024

Understanding snow saltation parameterizations: lessons from theory, experiments and numerical simulations

Michael Lehning, Daniela Brito Melo, Armin Sigmund

Drifting and blowing snow are important features in polar and high mountain regions. They control the surface mass balance in windy conditions and influence sublimation of snow and ice surfaces. Despite their importance, model representations in weather an ...

2024

Cross-code verification of non-neutral ABL and single wind turbine wake modelling in LES

Fernando Porté Agel, Marwa Souaiby

Large Eddy Simulations (LES) of atmospheric boundary layer (ABL) flow with the actuator disc (AD) for turbine modelling is a widely used method of simulating wind farm flows. Hence, it is important to understand the requirements for achieving a good compar ...

IOP PUBLISHING LTD2023

Wind Turbine Wakes in Active Yaw Control: Numerical and Theoretical Studies

Mou Lin

In this thesis, we explore the best practice of simulating the wakes of the turbines under active yaw control (AYC) using large-eddy simulation (LES). In the first study, we validate the blade-element actuator disk model (ADM-BE) for a yawed wind turbine. ...

EPFL2023

An experimental and analytical study of wind turbine wakes under pressure gradient

Fernando Porté Agel, Arslan Salim Dar, Abraham Starbuck Gertler

This work is dedicated to the systematic investigation of wind turbine wakes under the effect of pressure gradients. Wind tunnel experiments are carried out with a wind turbine positioned on straight ramps of increasing angle such that it experiences an ap ...

2023

Dynamic stall characterisation and control for vertical-axis wind turbines

Sébastien Le Fouest

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 ...

EPFL2023

A wind tunnel study on cyclic yaw control: Power performance and wake characteristics

Fernando Porté Agel, Arslan Salim Dar, Guiyue Duan

In this study, wind-tunnel experiments are used to investigate cyclic yaw control as a wake mitigation strategy aiming to improve wind farm power production. The control strategy is applied to a single wind turbine and a wind farm comprising of a column of ...

Elsevier2023

Wind farm power density optimization according to the area size using a novel self-adaptive genetic algorithm

Fernando Porté Agel, Nicolas Otto Kirchner Bossi

This work studies the power density (PD) optimization in wind farms, and its sensitivity to the available area size. A novel genetic algorithm (PDGA) is introduced, which optimizes PD and the turbine layout, by self-adapting to the PD and to the solutions ...

Pergamon-Elsevier Science Ltd2023

Time scales of dynamic stall development on a vertical-axis wind turbine blade

Sébastien Le Fouest, Karen Ann J Mulleners, Daniel Marie Fernex

Vertical-axis wind turbines are excellent candidates to diversify wind energy technology, but their aerodynamic complexity limits industrial deployment. To improve the efficiency and lifespan of vertical-axis wind turbines, we desire data-driven models and ...

2023

Wind Defiant Morphing Drones

Dario Floreano, Victor Casas Rochel, Nathan Samuel Müller, Charalampos Vourtsis, William John Stewart

Intense winds are a challenge for vertical take-off and landing drones with wings. In particular, in the hovering regime, wings are sensitive to wind currents that can be detrimental to their operational and energetic performances. Tail-sitters are particu ...

2023

Characterization of wind turbine flow through nacelle-mounted lidars: a review

Fernando Porté Agel, Peter Andreas Brugger

This article provides a comprehensive review of the most recent advances in the planning, execution, and analysis of inflow and wake measurements from nacelle-mounted wind Doppler lidars. Lidars installed on top of wind turbines provide a holistic view of ...

2023

Laterally unconfined neutral or negative buoyancy inflow into a quiescent ambient over sloping bottom

Haoran Shi

This work studies the nearshore hydrodynamics of a shallow turbulent flow entering a laterally unconfined quiescent ambient with a sloping bottom boundary. Examples of such flow are neutrally buoyant ebb tidal jets and hyperpycnal river plumes entering ope ...

EPFL2023

Combining Weather Station Data and Short-Term LiDAR Deployment to Estimate Wind Energy Potential with Machine Learning: A Case Study from the Swiss Alps

Michael Lehning, Wolf Hendrik Huwald, Franziska Gerber, Jérôme François Sylvain Dujardin, Fanny Kristianti

Wind energy potential in complex terrain is still poorly understood and difficult to quantify. With Switzerland’s current efforts to shift to renewable energy resources, it is now becoming even more crucial to investigate the hidden potential of wind energ ...

2023

Earwig-inspired foldable origami wing for micro air vehicle gliding

Jamie Paik, Risa Ishiguro

Foldable wings serve as an effective solution for reducing the size of micro air vehicles (MAVs) during non-flight phases, without compromising the gliding capacity provided by the wing area. Among insects, earwigs exhibit the highest folding ratio in thei ...

Frontiers Media Sa2023

Lab-Scale Investigation of the Integrated Backup/Storage System for Wind Turbines Using Alkaline Electrolyzer

Jan Van Herle, Hossein Pourrahmani

The depletion of fossil fuel sources has encouraged the authorities to use renewable resources such as wind energy to generate electricity. A backup/storage system can improve the performance of wind turbines, due to fluctuations in power demand. The novel ...

MDPI2023

Power Production and Blade Fatigue of a Wind Turbine Array Subjected to Active Yaw Control

Fernando Porté Agel, Mou Lin

This study investigated the power production and blade fatigue of a three-turbine array subjected to active yaw control (AYC) in full-wake and partial-wake configurations. A framework of a two-way coupled large eddy simulation (LES) and an aeroelastic blad ...

MDPI2023

Interactions of Cavitation Bubbles with Deformable Interfaces

Armand Baptiste Sieber

Cavitation is a topic that has long been of interest due to the large and growing range of applications associated with it. This is mainly because the collapse of cavitation bubbles releases a considerable amount of energy into the surrounding environment. ...

EPFL2023