Concept

Cisaillement (météorologie)

Publications associées (373)

How well do we understand the influence of drifting and blowing snow in extreme environments?

Varun Sharma, Michael Lehning, Jérôme François Sylvain Dujardin, Franziska Gerber, Benjamin Andreas Walter

Extreme cold environments such as the polar regions and high mountain areas are characterised by unknown precipitation quantities and a high variability of snow and ice masses. A key player in understanding the surface mass balance in these areas is drifti ...

2019

Fisher–Shannon Complexity Analysis of High-Frequency Urban Wind Speed Time Series

Dasaraden Mauree, Fabian Guignard

One-hertz wind time series recorded at different levels (from 1.5–25.5 m) in an urban area are investigated by using the Fisher–Shannon (FS) analysis. FS analysis is a well-known method to gain insight into the complex behavior of nonlinear systems, by qua ...

2019

Wind Energy Prediction in Highly Complex Terrain by Computational Fluid Dynamics

Fernando Porté Agel, Jiannong Fang, Daniel Jacob Tabas

With rising levels of wind power penetration in global electricity production, the relevance of wind power prediction is growing. More accurate forecasts reduce the required total amount of energy reserve capacity needed to ensure grid reliability and the ...

2019

Wavelet variance scale-dependence as a dynamics discriminating tool in high-frequency urban wind speed time series

Dasaraden Mauree, Fabian Guignard

High frequency wind time series measured at different heights from the ground (from 1.5 to 25.5 meters) in an urban area were investigated by using the variance of the coefficients of their wavelet transform. Two ranges of scales were identified, sensitive ...

2019

Cohesion-Induced Enhancement of Aeolian Saltation

Michael Lehning, Johan Alexandre Philippe Gaume, Francesco Comola

The wind-driven saltation of granular material plays a key role in various geophysical processes on Earth, Mars, Venus, and Titan. Although interparticle cohesion is known to limit the number of grains lifted from the surface through aerodynamic entrainmen ...

AMER GEOPHYSICAL UNION2019

Roll-up region of tip vortex: numerical investigation

Mohamed Farhat, Azin Amini, Matthieu Dreyer, Martino Reclari

The appearance of gas-filled vortices at the tip of hydraulic machines blades is usually associated with increase of losses, vibrations, noise and erosion risk. The understanding of the roll-up region, where the boundary layer on the pressure side crosses ...

IOP PUBLISHING LTD2019

Machine learning and geographic information systems for large-scale wind energy potential estimation in rural areas

Jean-Louis Scartezzini, Dasaraden Mauree, Dan Assouline, Nahid Mohajeri Pour Rayeni

Clean, safe, affordable and available in the long-term, wind is one of the most promising sources of renewable energy. Its optimized and profitable use, however, requires an estimation of the potential in locations of interest, given its very volatile beha ...

IOP2019

On the fine vertical structure of the low troposphere over the coastal margins of East Antarctica

Alexis Berne, Etienne Gabriel Henri Vignon

In this study, 8 years of high-resolution radiosonde data at nine Antarctic stations are analysed to provide the first large-scale characterization of the fine vertical structure of the low troposphere up to 3 km altitude over the coastal margins of East A ...

Copernicus GmbH2019

Coherent Structure Interaction During Unsteady Separation

Karen Ann J Mulleners

Unsteady flow separation in rotationally augmented flow fields plays a significant role in the aerodynamic performance of industrial rotors, including wind turbines. Current computational models underestimate the aerodynamic loads due to the inaccurate pre ...

2019

Energetic ion losses 'channeling' mechanism and strategy for mitigation

Olivier Sauter, Ambrogio Fasoli, Basil Duval, Stefano Coda, Jonathan Graves, Yves Martin, Duccio Testa, Patrick Blanchard, Alessandro Pau, Cristian Sommariva, Henri Weisen, Richard Pitts, Yann Camenen, Jan Horacek, Javier García Hernández, Marco Wischmeier, Nicola Vianello, Mikhail Maslov, Federico Nespoli, Yao Zhou, David Pfefferlé, Davide Galassi, Antonio José Pereira de Figueiredo, Jonathan Marc Philippe Faustin, Liang Yao, Dalziel Joseph Wilson, Hamish William Patten, Samuel Lanthaler, Bernhard Sieglin, Otto Asunta

Results from two different sets of JET experiments are presented. In experiments in which toroidicity-induced Alfven eigenmodes (TAEs) localized at different radial locations had the same frequencies and toroidal mode numbers, the occurrence of enhanced lo ...

2019

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