scholarly journals Temporal structure of aggregate power fluctuations in large-eddy simulations of extended wind-farms

2014 ◽  
Vol 6 (4) ◽  
pp. 043102 ◽  
Author(s):  
Richard J. A. M. Stevens ◽  
Charles Meneveau
Keyword(s):  
Temporal Structure ◽  
Wind Farms ◽  
Large Eddy Simulations ◽  
Large Eddy ◽  
Power Fluctuations

scholarly journals Quantifying variability of Large Eddy Simulations of very large wind farms

2015 ◽  
Vol 625 ◽  
pp. 012027 ◽  
Author(s):  
S J Andersen ◽  
B Witha ◽  
S-P Breton ◽  
J N Sørensen ◽  
R F Mikkelsen ◽  
...  
Keyword(s):  
Wind Farms ◽  
Large Eddy Simulations ◽  
Large Eddy ◽  
Large Wind

scholarly journals Evaluation of the the wind farm wake parametrization with large-eddy simulations of wakes in WRF

2021 ◽  
Author(s):  
Alfredo Peña ◽  
Jeffrey Mirocha
Keyword(s):  
Boundary Layer ◽  
Wind Farm ◽  
Wrf Model ◽  
Wind Farms ◽  
Large Eddy Simulations ◽  
Disk Model ◽  
Mesoscale Models ◽  
Boundary Layer Height ◽  
Wind Speeds ◽  
Large Eddy

<p>Mesoscale models, such as the Weather Research and Forecasting (WRF) model, are now commonly used to predict wind resources, and in recent years their outputs are being used as inputs to wake models for the prediction of the production of wind farms. Also, wind farm parametrizations have been implemented in the mesoscale models but their accuracy to reproduce wind speeds and turbulent kinetic energy fields within and around wind farms is yet unknown. This is partly because they have been evaluated against wind farm power measurements directly and, generally, a lack of high-quality observations of the wind field around large wind farms. Here, we evaluate the in-built wind farm parametrization of the WRF model, the so-called Fitch scheme that works together with the MYNN2 planetary boundary layer (PBL) scheme against large-eddy simulations (LES) of wakes using a generalized actuator disk model, which was also implemented within the same WRF version. After setting both types of simulations as similar as possible so that the inflow conditions are nearly identical, preliminary results show that the velocity deficits can differ up to 50% within the same area (determined by the resolution of the mesoscale run) where the turbine is placed. In contrast, within that same area, the turbine-generated TKE is nearly identical in both simulations. We also prepare an analysis of the sensitivity of the results to the inflow wind conditions, horizontal grid resolution of both the LES and the PBL run, number of turbines within the mesoscale grid cells, surface roughness, inversion strength, and boundary-layer height.</p>

scholarly journals Modeling dynamic wind direction changes in large eddy simulations of wind farms

2021 ◽  
Vol 170 ◽  
pp. 1342-1352
Author(s):  
Anja Stieren ◽  
Srinidhi N. Gadde ◽  
Richard J.A.M. Stevens
Keyword(s):  
Wind Direction ◽  
Wind Farms ◽  
Large Eddy Simulations ◽  
Large Eddy

scholarly journals A concurrent precursor inflow method for Large Eddy Simulations and applications to finite length wind farms

2014 ◽  
Vol 68 ◽  
pp. 46-50 ◽  
Author(s):  
Richard J.A.M. Stevens ◽  
Jason Graham ◽  
Charles Meneveau
Keyword(s):  
Finite Length ◽  
Wind Farms ◽  
Large Eddy Simulations ◽  
Large Eddy

Large Eddy Simulations of Francis Turbine Operating at Ultra-Low Loads

2020 ◽  
Author(s):  
Muhannad Altimemy ◽  
Justin Caspar ◽  
Saif Watheq ◽  
Alparslan Oztekin
Keyword(s):  
Turbulent Flows ◽  
Structural Integrity ◽  
Draft Tube ◽  
Temporal Structure ◽  
Pressure Fluctuations ◽  
High Amplitude ◽  
Large Eddy Simulations ◽  
Francis Turbine ◽  
Partial Load ◽  
Large Eddy

Abstract High-fidelity large eddy simulations (LES) were conducted to characterize the spatial and temporal structure of turbulent flows in an industrial-sized Francis turbine. The unit operated at 50% and 40% of the best efficiency design flowrate. Contours of vorticity, velocity, pressure, and iso-surfaces of Q-Criterion were presented to characterize the effects on the draft tube. Probes placed alongside the draft tube measure the pressure signal to investigate the flow-induced pressure fluctuations inside the turbine unit. The maximum intensity of pressure fluctuations at 50% partial load was 22.66% of the turbine head, while the strength of the pressure fluctuations was 26.36% at 40% partial load. A large number of unorganized smaller vortices observed in the draft tube contribute to the creation of pressure fluctuations. Two pressure modes can be easily recognized (1) high frequency with low amplitude pressure fluctuations and (2) low frequency with high amplitude fluctuations. These pressure fluctuations could be harmful to the structural integrity of the unit and also have undesirable influences on the operational stability of the hydro-turbines.

scholarly journals Large eddy simulations of the effect of vertical staggering in large wind farms

Wind Energy ◽  
2018 ◽  
Vol 22 (2) ◽  
pp. 189-204 ◽  
Author(s):  
Mengqi Zhang ◽  
Mark G. Arendshorst ◽  
Richard J. A. M. Stevens
Keyword(s):  
Wind Farms ◽  
Large Eddy Simulations ◽  
Large Eddy ◽  
Large Wind

scholarly journals Parallel Large Eddy Simulations of Wind Farms with the Actuator Line Method

2013 ◽  
Vol 61 ◽  
pp. 227-232 ◽  
Author(s):  
A. Baez-Vidal ◽  
O. Lehmkuhl ◽  
D.M. Valdivieso ◽  
C.D. Pérez Segarra
Keyword(s):  
Wind Farms ◽  
Large Eddy Simulations ◽  
Line Method ◽  
Large Eddy
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