Turbulent kinetics of a large wind farm and their impact in the neutral boundary layer

High-resolution large-eddy simulation of the flow over a large wind farm (64 wind turbines) is performed using the HIGRAD/FIRETEC-WindBlade model, which is a high-performance computing wind turbine–atmosphere interaction model that uses the Lagrangian actuator line method to represent rotating turbine blades. These high-resolution large-eddy simulation results are used to parameterize the thrust and power coefficients that contain information about turbine interference effects within the wind farm. Those coefficients are then incorporated into the WRF (Weather Research and Forecasting) model in order to evaluate interference effects in larger-scale models. In the high-resolution WindBlade wind farm simulation, insufficient distance between turbines creates the interference between turbines, including significant vertical variations in momentum and turbulent intensity. The characteristics of the wake are further investigated by analyzing the distribution of the vorticity and turbulent intensity. Quadrant analysis in the turbine and post-turbine areas reveals that the ejection motion induced by the presence of the wind turbines is dominant compared to that in the other quadrants, indicating that the sweep motion is increased at the location where strong wake recovery occurs. Regional-scale WRF simulations reveal that although the turbulent mixing induced by the wind farm is partly diffused to the upper region, there is no significant change in the boundary layer depth. The velocity deficit does not appear to be very sensitive to the local distribution of turbine coefficients. However, differences of about 5% on parameterized turbulent kinetic energy were found depending on the turbine coefficient distribution. Therefore, turbine coefficients that consider interference in the wind farm should be used in wind farm parameterization for larger-scale models to better describe sub-grid scale turbulent processes.

[1]  B. Kosović,et al.  Resolved Turbulence Characteristics in Large-Eddy Simulations Nested within Mesoscale Simulations Using the Weather Research and Forecasting Model , 2014 .

[2]  Lance Manuel,et al.  Large-eddy simulation of stable boundary layer turbulence and estimation of associated wind turbine loads , 2014 .

[3]  Roger H. Shaw,et al.  Canopy element influences on resolved- and subgrid-scale energy within a large-eddy simulation , 2003 .

[4]  Rebecca J. Barthelmie,et al.  Analytical modelling of wind speed deficit in large offshore wind farms , 2006 .

[5]  Rodman R. Linn,et al.  Coupled Atmospheric Fire Modeling Employing the Method of Averages , 2000 .

[6]  Hao Lu,et al.  Interaction between large wind farms and the atmospheric boundary layer , 2014 .

[7]  Neil Kelley,et al.  Using Dynamically Coupled Turbine/Wind Simulations to Investigate the Influence of Atmospheric Turbulence in Turbine Wake Recovery , 2010 .

[8]  D. Muñoz‐Esparza,et al.  A stochastic perturbation method to generate inflow turbulence in large-eddy simulation models: Application to neutrally stratified atmospheric boundary layers , 2015 .

[9]  Joon Sang Lee,et al.  Investigation of Kelvin–Helmholtz instability in the stable boundary layer using large eddy simulation , 2014 .

[10]  L. Margolin,et al.  MPDATA: A Finite-Difference Solver for Geophysical Flows , 1998 .

[11]  F. H. Harlow,et al.  FIRETEC: A transport description of wildfire behavior , 1997 .

[12]  Fernando Porté-Agel,et al.  Wind-Turbine Wakes in a Convective Boundary Layer: A Wind-Tunnel Study , 2013, Boundary-Layer Meteorology.

[13]  F. Porté-Agel,et al.  Large-eddy simulation of a very large wind farm in a stable atmospheric boundary layer , 2011 .

[14]  Judith A. Curry,et al.  A Large Eddy Simulation Study of a Quasi-Steady, Stably Stratified Atmospheric Boundary Layer , 2000 .

[15]  Jimy Dudhia,et al.  Local and mesoscale impacts of wind farms as parameterized in a mesoscale NWP model , 2012 .

[16]  François Pimont,et al.  Validation of FIRETEC wind-flows over a canopy and a fuel-break , 2009 .

[17]  Ronald G. Prinn,et al.  Potential climatic impacts and reliability of large-scale offshore wind farms , 2011 .

[18]  David W. Keith,et al.  On the Climate Impact of Surface Roughness Anomalies , 2008 .

[19]  J. Lundquist,et al.  Parameterization of Wind Farms in Climate Models , 2013 .

[20]  J. Jonkman,et al.  Definition of a 5-MW Reference Wind Turbine for Offshore System Development , 2009 .

[21]  E. Koo,et al.  Large-Eddy Simulations of Air Flow and Turbulence within and around Low-Aspect-Ratio Cylindrical Open-Top Chambers , 2013 .

[22]  R. Prinn,et al.  Potential climatic impacts and reliability of very large-scale wind farms , 2009 .

[23]  Wind Energy and Climate: Modeling the Atmospheric Impacts of Wind Energy Turbines , 2007 .

[24]  R. Stull.  An Introduction to Boundary Layer Meteorology , 1988 .

[25]  Fernando Porté-Agel,et al.  Large-eddy simulation of atmospheric boundary layer flow through wind turbines and wind farms , 2011 .

[26]  Erik Lundtang Petersen,et al.  Wind power meteorology. Part I: climate and turbulence , 1998 .

[27]  D. Muñoz‐Esparza,et al.  Bridging the Transition from Mesoscale to Microscale Turbulence in Numerical Weather Prediction Models , 2014, Boundary-Layer Meteorology.

[28]  Somnath Baidya Roy,et al.  Impacts of wind farms on surface air temperatures , 2010, Proceedings of the National Academy of Sciences.

[29]  Mikio Nakanish,et al.  Improvement Of The Mellor–Yamada Turbulence Closure Model Based On Large-Eddy Simulation Data , 2001 .

[30]  J. Sørensen,et al.  Wind turbine wake aerodynamics , 2003 .

[31]  David W Keith,et al.  The influence of large-scale wind power on global climate. , 2004, Proceedings of the National Academy of Sciences of the United States of America.

[32]  S. Pacala,et al.  Can large wind farms affect local meteorology , 2003 .