Publications de Marc Calaf Bracons

Mean kinetic energy distribution in finite-size wind farms: A function of turbines' arrangement

Varun Sharma, Marc Calaf Bracons, Roberto Torres Sánchez

In this work the redistribution and recovery of mean kinetic energy in a realistic, finite size wind farm is studied for neutral atmospheric boundary layer conditions. Five different wind farm configurations, with different wind turbine arrangements, are c ...

Pergamon-Elsevier Science Ltd2020

Evolution of flow characteristics through finite-sized wind farms and influence of turbine arrangement

Marc Calaf Bracons, Varun Sharma, Marc Parlange, Fabien Margairaz

Pergamon-Elsevier Science Ltd2018

Pathways for mitigating thermal losses in solar photovoltaics

Marc Calaf Bracons, Olivier Denis Dupré

To improve the performance of solar photovoltaic devices one should mitigate three types of losses: optical, electrical and thermal. However, further reducing the optical and electrical losses in modern photovoltaic devices is becoming increasingly costly. ...

Nature Research2018

Wind farm density and harvested power in very large wind farms: A low-order model

Varun Sharma, Marc Calaf Bracons

In this work we create new understanding of wind turbine wakes recovery process as a function of wind farm density using large-eddy simulations of an atmospheric boundary layer diurnal cycle. Simulations are forced with a constant geostrophic wind and a ti ...

Amer Physical Soc2017

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

Perturbations to the Spatial and Temporal Characteristics of the Diurnally-Varying Atmospheric Boundary Layer Due to an Extensive Wind Farm

Varun Sharma, Marc Parlange, Marc Calaf Bracons

The effect of extensive terrestrial wind farms on the spatio-temporal structure of the diurnally-evolving atmospheric boundary layer is explored. High-resolution large-eddy simulations of a realistic diurnal cycle with an embedded wind farm are performed. ...

Springer Verlag2017

Controls on the diurnal streamflow cycles in two subbasins of an alpine headwater catchment

Marc Parlange, Steven Vincent Weijs, Marc Calaf Bracons, Holly Jayne Oldroyd, Raphaël Mutzner

In high-altitude alpine catchments, diurnal streamflow cycles are typically dominated by snowmelt or ice melt. Evapotranspiration-induced diurnal streamflow cycles are less observed in these catchments but might happen simultaneously. During a field campai ...

American Geophysical Union2015

Time-adaptive wind turbine model for an LES framework

Varun Sharma, Michael Lehning, Marc Parlange, 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

Large Wind Farms and the Scalar Flux over an Heterogeneously Rough Land Surface

Marc Parlange, Chad Higgins, Marc Calaf Bracons

The influence of surface heterogeneities extends vertically within the atmospheric surface layer to the so-called blending height, causing changes in the fluxes of momentum and scalars. Inside this region the turbulence structure cannot be treated as horiz ...

Springer Verlag2014

Coherent structures and the k(-1) spectral behaviour

Valentin Simeonov, Marc Parlange, Marc Calaf Bracons, Holly Jayne Oldroyd

l Here we present unique evidence of a k(-1) scaling behaviour in the atmospheric boundary layer and its connection to large scale coherent structures within the boundary layer. Wind lidar measurements were conducted above a lake under cold atmospheric con ...

Amer Inst Physics2013