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Concept

Girouette

Publications associées (16)

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

An evaluation of new particle formation events in Helsinki during a Baltic Sea cyanobacterial summer bloom

Lubna Dada

Several studies have investigated new particle formation (NPF) events from various sites ranging from pristine locations, including forest sites, to urban areas. However, there is still a dearth of studies investigating NPF processes and subsequent aerosol ...

Copernicus GmbH2022

Radar processing techniques to study summer snowfall in the Sør Rondane Mountains, Antarctica

Alfonso Ferrone

Snowfall is one of the main positive contributors to the surface mass balance of the Antarctic ice sheet. There are several techniques to monitor solid precipitation on the continent. Among them, meteorological radars provide the means to characterize the ...

EPFL2022

Experimental investigation and analytical modelling of active yaw control for wind farm power optimization

Fernando Porté Agel, Haohua Zong

In this study, the physics and effectiveness of active yaw control under various wind conditions are investigated systematically, based on wind tunnel experiments and a new analytical wind farm model. The power and wake velocity measurements of a three-row ...

Pergamon-Elsevier Science Ltd2021

Monitoring of Torque Induced Strain in Composite Shafts with Embedded and Surface-Mounted Optical Fiber Bragg Gratings

John Botsis, Georgios Violakis, Georgios Pappas

In this study, silica glass, optical fiber Bragg gratings (FBGs) are used for torque-induced strain monitoring in carbon fiber reinforced polymer (CFRP) hollow shafts toward the development of a methodology for structural load monitoring. Optical fibers wi ...

2021

Using global reanalysis data to quantify and correct airflow distortion bias in shipborne wind speed measurements

Julia Schmale, Sebastian Johannes Heinz-Josef Landwehr

At sea, wind forcing is responsible for the formation and development of surface waves and represents an important source of near-surface turbulence. Therefore, processes related to near-surface turbulence and wave breaking, such as sea spray emission and ...

2020

Wind Turbine Wakes in Directionally Varying Wind Shears

Fernando Porté Agel, Mahdi Abkar

In the atmospheric boundary layer, the Coriolis force associated with the Earth’s rotation induces a spanwise wind shear in addition to the wall-normal one leading to a continuous change in wind direction with height. The spanwise wind shear in directional ...

2019

Investigation of the incoming wind vector for improved wind turbine yaw-adjustment under different atmospheric and wind farm conditions

Varun Sharma, Marc Calaf Bracons

Regardless of the evolution of wind energy harvesting, the way in which turbines obtain in-situ meteorological information remains the same - i.e. using traditional wind vanes and cup anemometers installed at the turbine's nacelle, right behind the blades. ...

Pergamon-Elsevier Science Ltd2017

A new wind-farm parameterization for large-scale atmospheric models

Fernando Porté Agel, Mahdi Abkar

In this article, a new model is developed to parameterize the effect of wind farms in large-scale atmospheric models such as weather models. In the new model, wind turbines in a wind farm are parameterized as elevated sinks of momentum and sources of turbu ...

Amer Inst Physics2015

Time-adaptive wind turbine model for an LES framework

Michael Lehning, Marc Parlange, Varun Sharma, Marc Calaf Bracons

Most large-eddy simulation studies related to wind energy have been carried out either by using a fixed pressure gradient to ensure that mean wind direction is perpendicular to the wind turbine rotor disk or by forcing the flow with a geostrophic wind and ...

Wiley-Blackwell2015

Momentum balance of katabatic flow on steep slopes covered with short vegetation

Marc Parlange, Gabriel George Katul, Eric Richard Pardyjak, Holly Jayne Oldroyd

Katabatic flows over alpine mountainous terrain differ from their forested or bare slope counterparts due to the presence of well-ventilated, short vegetation. The impact of a grass canopy and larger-scale pressure perturbations on the one-dimensional mean ...

American Geophysical Union2014

Direct effects of dominant winds on residence and travel times in the wide and open lacustrine embayment: Vidy Bay (Lake Geneva, Switzerland)

David Andrew Barry, Tamar Kohn, Ulrich Lemmin, Roham Bakhtyar, Florence Bonvin, Amir Mehdi Razmi

Numerical simulations were carried out to determine the residence (or flushing) time of water in Vidy Bay (north shore of Lake Geneva) for different meteorological conditions. A hydrodynamic model (Delft3DFLOW) was applied to simulate the flow field in the ...

Springer Verlag2014

A Numerical Study of the Effects of Wind Direction on Turbine Wakes and Power Losses in a Large Wind Farm

Fernando Porté Agel, Yu-Ting Wu

In this study, large-eddy simulations (LESs) were performed to investigate the effects of changing wind direction on the turbine wakes and associated power losses in the Horns Rev offshore wind farm. In the LES framework, the turbulent subgrid-scale stress ...

Mdpi Ag2013

A Plume Tracking Algorithm Based on Crosswind Formations

Alcherio Martinoli, Inaki Navarro Oiza, Thomas Lochmatter

We introduce a plume tracking algorithm based on robot formations. The algorithm is inherently designed for multi-robot systems, and requires at least two robots to collaborate. The robots try to keep themselves centered around the plume while moving upwin ...

Springer-Verlag Berlin2013

Stochastic Control and Free Boundary Problems for Sailboat Trajectory Optimization

Laura Claudia Catherine Vinckenbosch

The topic of this thesis is the study of several stochastic control problems motivated by sailing races. The goal is to minimize the travel time between two locations, by selecting the fastest route in face of randomly changing weather conditions, such as ...

EPFL2012

The Effects of Building Representation and Clustering in Large-Eddy Simulations of Flows in Urban Canopies

Marc Parlange

We perform large-eddy simulations of neutral atmospheric boundary-layer flow over a cluster of buildings surrounded by relatively flat terrain. The first investigated question is the effect of the level of building detail that can be included in the numeri ...

2009