Article
Green & Sustainable Science & Technology
Arslan Salim Dar, Fernando Porte-Agel
Summary: The study investigates the wake behind a wind turbine located on an escarpment using particle image velocimetry in a wind tunnel. Different escarpment models result in significant differences in the turbine wake characteristics, with forward facing steps inducing faster wake recovery and higher turbulence kinetic energy compared to ramp-shaped escarpments. The velocity deficit profiles in the far wake exhibit self-similar behavior, with a larger wake growth rate in the vertical direction than in the lateral direction.
Article
Green & Sustainable Science & Technology
Zein Sadek, Ryan Scott, Nicholas Hamilton, Raul Bayoan Cal
Summary: A new three-dimensional steady-state wake model is proposed, improving the wake description by incorporating local flow acceleration near the rotor. Compound and normal Gaussian functions are used to concisely describe wake structures such as momentum deficit and regions of accelerated flow. With the use of large-eddy simulations as training data, the model is developed for two in-line turbines under various inflow conditions. It demonstrates comparable or even better performance in terms of relative error and mass consistency compared to existing work, and shows a high degree of flexibility in scaling across different inflow conditions by utilizing empirical correlations.
Article
Environmental Sciences
Nils Christiansen, Jeffrey R. R. Carpenter, Ute Daewel, Nobuhiro Suzuki, Corinna Schrum
Summary: This study investigates the structure drag and physical impacts of offshore wind turbines on the marine environment of the German Bight. Two modeling approaches for simulating wind turbine foundation effects are presented, and the use of very high resolution in hydrostatic modeling is discussed. The study demonstrates the impacts of monopile drag on hydrodynamic conditions using a low-resolution structure drag parameterization, validated against in-situ measurements. The simulations show that structure-induced mixing affects regional scales due to additional turbulence production, leading to changes in current velocities and stratification.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Green & Sustainable Science & Technology
Arslan Salim Dar, Guillem Armengol Barcos, Fernando Porte-Agel
Summary: Wind-tunnel experiments were conducted to investigate the impact of minor modifications to the roof edge shape on the power performance and wake characteristics of a horizontal-axis wind turbine on a cube-shaped building. The study found that the power performance of the turbine and the wake characteristics are influenced by the roof edge shape.
Article
Environmental Sciences
Jeanie A. Aird, Eliot W. Quon, Rebecca J. Barthelmie, Mithu Debnath, Paula Doubrawa, Sara C. Pryor
Summary: This study successfully identified and characterized wind turbine wakes using a region-based convolutional neural network, even in complex terrain and varying resolutions. The model exhibited high success rate and robustness in recognizing wakes, with characteristics consistent with expected behaviors under different meteorological conditions.
Article
Green & Sustainable Science & Technology
W. Chanprasert, R. N. Sharma, J. E. Cater, S. E. Norris
Summary: This study investigates the influence of directionally sheared inflows on wake interaction in a four-inline turbine array using a coupled Large Eddy Simulation (LES) and turbine aeroelastic code. The results show that the lateral velocity of the ambient wind affects wake rotations, resulting in differences in radial wake expansion and wake shape twist angle. Symmetric wakes in the zero directional shear case lead to lower fatigue loads on the blades and rotor shaft compared to skewed wakes. The flapwise blade-root bending moment of downstream turbines is approximately three times higher under wind veering (Northern Hemisphere) than under wind backing (Southern Hemisphere).
Article
Engineering, Civil
Antonio M. G. Lopes, Antonio H. S. N. Vicente, Omar H. Sanchez, Regina Daus, Herbert Koch
Summary: This study evaluates several available analytical wake models that correct the computed wind field by CFD as postprocessing tools. Validation was done using experimental SCADA data from an onshore wind farm with 8 wind turbines, analyzing computed velocity ratios relative to the upstream leading turbine in single and multiple wake situations.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2022)
Article
Environmental Sciences
Nikolas Angelou, Mikael Sjoholm
Summary: Wind lidars are used in wind turbines to monitor inflow and enhance data reliability and monitoring efficiency. A new method based on modeling the radial speed contribution generated by the turbine blades is proposed to distinguish between wind and blade signals.
Article
Green & Sustainable Science & Technology
Linlin Tian, Yilei Song, Pengcheng Xiao, Ning Zhao, Wenzhong Shen, Chunling Zhu
Summary: Accurate prediction of wake turbulence level is crucial in wind farm design for turbine power and load evaluation. However, there is still a knowledge gap on wake turbulence characteristics and little work has been done on related engineering models. In this study, one-dimensional analytical models are proposed and validated to estimate wake width and maximum wake turbulence level at any streamwise positions. Based on these, a highly simplified three-dimensional cosine shape (3D-COTI) model is proposed to effectively estimate wake turbulence intensity, considering wind shear and ground effects. Model evaluations with various turbine types and inflow conditions show good agreement with measurements on turbulence distribution within the wake flow. Due to its accuracy, simplicity, and universality, the proposed model has potential for large-scale wind farm applications.
Article
Energy & Fuels
Jennifer Marie Rinker, Esperanza Soto Sagredo, Leonardo Bergami
Summary: This study investigates the effect of replacing wake meandering with spatially varying statistics in wind farms, and compares the accuracy of aeroelastic response simulations using different wake-model fidelities. The results show that prescribing the profile function for the standard deviation is beneficial for tower-base fore-aft moment, while other load channels have similar accuracies for both medium- and low-fidelity models.
Article
Chemistry, Multidisciplinary
Vincenzo Sepe, Alberto Maria Avossa, Fabio Rizzo, Francesco Ricciardelli
Summary: This paper explores the applicability of Lidar wind measurements for calibrating mean wind profiles in terms of time and space extension. The logarithmic wind speed profiles corresponding to different site conditions are obtained, and pseudo-experimental wind speed profiles are generated by adding Gaussian-distributed noise to simulate measurement errors. Least-square fitting is applied to identify the roughness length and the zero-plane displacement. The results show an increase in the scatter of the estimated parameters with increasing elevation of the lowest measurement point. A parametric study is conducted to analyze the influence of the number of available experimental profiles on the uncertainty associated with the estimated parameters of the logarithmic law. It is concluded that measurements at low elevations are essential for identifying the logarithmic mean wind profile using a reasonable number of observations.
APPLIED SCIENCES-BASEL
(2023)
Article
Energy & Fuels
Davide Cazzaro, Gabriele Bedon, David Pisinger
Summary: Vertical Axis Wind Turbines (VAWTs) offer advantages over Horizontal Axis Wind Turbines (HAWTs), such as higher power densities and reduced wakes. The optimization of wind farm layouts is crucial for extracting more energy. In this study, we develop an optimizer for VAWTs that considers various layouts and obstacles. We also present a novel model for wind farm optimization that takes into account the rotation of turbines, increasing total energy production.
Article
Green & Sustainable Science & Technology
Simon D. Hornshoj-Moller, Peter D. Nielsen, Pourya Forooghi, Mahdi Abkar
Summary: This study quantifies the structural uncertainties of RANS models in simulating wake flow behind a stand-alone wind turbine by introducing perturbations to the Reynolds stress tensor. The k-ω SST model tends to predict higher levels of isotropy in the turbulent wake, and adjustments in perturbation amount are needed to improve agreement with LES data.
Article
Green & Sustainable Science & Technology
Yunliang Li, Zhaobin Li, Zhideng Zhou, Xiaolei Yang
Summary: Large-eddy simulation was used to investigate the effects of forest canopy on wind turbine wakes. Results showed that wake recovery was faster in forest canopies compared to flat terrain. Turbulence kinetic energy (TKE) decreased significantly in the lower part of the wake above the forest, while increased mainly at the top tip. Power spectral density analysis revealed different frequency ranges of TKE increase for forest canopy and flat cases. The leaf area index (LAI) had a greater impact on wake-added TKE and wake-added Reynolds shear stress compared to the vertical distribution of leaf area density (LAD).
Article
Energy & Fuels
Arslan Salim Dar, Fernando Porte-Agel
Summary: In this study, a modeling framework for wind turbine wakes under an arbitrary pressure gradient imposed by the base flow is presented. The model is validated against experimental data and found to agree well.
Article
Green & Sustainable Science & Technology
Geng Xia, Caroline Draxl, Ajay Raghavendra, Julie K. Lundquist
Summary: The study investigates the ability of the WRF model to simulate mountain waves and their impact on hub-height wind speed, showing moderate skill in simulating observed mountain waves. The Fast Fourier Transform can calculate the simulated mountain wave impact on wind speed, which agrees well with SoDAR observations in terms of magnitude and pattern. WRF consistently predicts impacts of significant mountain wave events about an hour earlier than actual observations in simulated cases.
Article
Meteorology & Atmospheric Sciences
Alex Rybchuk, Caroline B. Alden, Julie K. Lundquist, Gregory B. Rieker
Summary: The evaluation of the WRF-LES model in this study found that the model accurately simulates surface concentrations under strong convection conditions, but substantially overpredicts concentrations under weak convection. This may be attributed to the model's alignment with local free convection theory and minimal use of parameterized turbulent energy in strong convective conditions.
MONTHLY WEATHER REVIEW
(2021)
Article
Meteorology & Atmospheric Sciences
Robert S. Arthur, Timothy W. Juliano, Bianca Adler, Raghavendra Krishnamurthy, Julie K. Lundquist, Branko Kosovic, Pedro A. Jimenez
Summary: In this article, we demonstrate how a new framework for modeling atmospheric turbulence improves cold pool predictions, using a case study from January 2017 in the Columbia River basin (U.S. Pacific Northwest). Cold pools are regions of cold, stagnant air that form within valleys or basins, and improved forecasts could help to mitigate the risks they pose to air quality, transportation, and wind energy production. For the chosen case study, our tests show a reduction in temperature and wind speed errors by up to a factor of 2-3 relative to standard model options. These results strongly motivate continued development of the framework as well as its application to other complex weather events.
JOURNAL OF APPLIED METEOROLOGY AND CLIMATOLOGY
(2022)
Article
Green & Sustainable Science & Technology
Miguel Sanchez Gomez, Julie K. Lundquist, Jeffrey D. Mirocha, Robert S. Arthur, Domingo Munoz-Esparza, Rachel Robey
Summary: Wind plant blockage reduces wind velocity, affecting power generation. The mechanisms and characteristics of the induction zone are not well understood. Field observations and numerical simulations are used to evaluate blockage in an Oklahoma wind plant. The study highlights the challenges of quantifying blockage and the impact of terrain effects.
JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY
(2022)
Article
Green & Sustainable Science & Technology
Mithu Debnath, Patrick Moriarty, Raghavendra Krishnamurthy, Nicola Bodini, Rob Newsom, Eliot Quon, Julie K. Lundquist, Stefano Letizia, Giacomo Valerio Iungo, Petra Klein
Summary: The American wake experiment (AWAKEN) is being conducted in northern Oklahoma, USA, near the Atmospheric Radiation Measurement Southern Great Plains (ARM SGP) atmospheric observatory. This study analyzes long-term wind data collected at the ARM SGP observatory to characterize the winds near the AWAKEN site. The analysis reveals a high occurrence of wind shear and veer events, especially nocturnal low-level jets, coming predominantly from the south and southeast. By using the Monin-Obukhov similarity theory (MOST) and comparing with observational data, the wind shear at the site can be predicted, with some limitations in the stable boundary layer.
JOURNAL OF RENEWABLE AND SUSTAINABLE ENERGY
(2023)
Article
Meteorology & Atmospheric Sciences
M. Sanchez Gomez, J. K. Lundquist, G. Deskos, S. R. Arwade, A. T. Myers, J. F. Hajjar
Summary: Offshore wind energy deployment in the U.S. is expected to increase in the coming years. However, current wind turbine design criteria may not account for the unique wind characteristics of tropical cyclones. Idealized simulations of five tropical cyclones reveal that wind conditions near the eyewall of Category 1, 2, and 3 storms can exceed current design standards, indicating the need for revised criteria.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Green & Sustainable Science & Technology
Miguel Sanchez Gomez, Julie K. Lundquist, Jeffrey D. Mirocha, Robert S. Arthur
Summary: Wind plants slow down the approaching wind, causing blockage and reducing the performance of front-row turbines and potentially those deeper into the array. The faster cooling rate at the surface amplifies blockage by producing stronger stably stratified flow in the boundary layer. Evaluating different terms in the momentum conservation equation within the turbine rotor layer helps understand the physical mechanisms amplifying blockage.
WIND ENERGY SCIENCE
(2023)
Article
Green & Sustainable Science & Technology
Paul Veers, Katherine Dykes, Sukanta Basu, Alessandro Bianchini, Andrew Clifton, Peter Green, Hannele Holttinen, Lena Kitzing, Branko Kosovic, Julie K. Lundquist, Johan Meyers, Mark O'Malley, William J. Shaw, Bethany Straw
Summary: Wind power is crucial for transitioning to renewable energy, but faces challenges in design, manufacture, and deployment. The wind research community has made efforts in understanding and addressing these challenges over the past three years.
WIND ENERGY SCIENCE
(2022)
Article
Green & Sustainable Science & Technology
Alex Rybchuk, Timothy W. Juliano, Julie K. Lundquist, David Rosencrans, Nicola Bodini, Mike Optis
Summary: This study compares the sensitivity of wind plant wakes to different boundary layer schemes and finds that the choice of boundary layer scheme affects hub-height wind speeds and capacity factors in wind plants. Therefore, it is recommended to consider the variability of boundary layer schemes in future wind plant planning and wind forecasting studies.
WIND ENERGY SCIENCE
(2022)
Article
Meteorology & Atmospheric Sciences
Rachel Robey, Julie K. Lundquist
Summary: This study investigates the distribution of measurement error due to turbulence in varying atmospheric stability using virtual WindCube V2 lidar simulations. The findings suggest that convective conditions are most prone to large errors, while vector time-averaged measurements can improve the behavior of the error distributions. Systematic analysis of the observation error helps to explain dominant mechanisms and support empirical results.
ATMOSPHERIC MEASUREMENT TECHNIQUES
(2022)
Article
Green & Sustainable Science & Technology
Vincent Pronk, Nicola Bodini, Mike Optis, Julie K. Lundquist, Patrick Moriarty, Caroline Draxl, Avi Purkayastha, Ethan Young
Summary: This study evaluates the performance of ERA-5 and WTK-LED in wind energy prediction. It is found that ERA-5 exhibits a significant negative bias in wind speed simulation, but outperforms WTK-LED in terms of centered root-mean-square error and correlation coefficient. The higher cRMSE of WTK-LED is caused by its tendency to overpredict the amplitude of the wind speed diurnal cycle and its failure to accurately capture wind plant wake effects.
WIND ENERGY SCIENCE
(2022)
Article
Green & Sustainable Science & Technology
Adam S. Wise, James M. T. Neher, Robert S. Arthur, Jeffrey D. Mirocha, Julie K. Lundquist, Fotini K. Chow
Summary: This study investigates the performance and wake behavior of wind turbines under different terrain conditions. The model used in the study is able to accurately simulate the observed behavior of wind turbine wakes. The results show that the wake of the wind turbine is influenced by the terrain and atmospheric stability, leading to different vertical deflections and persistence downstream.
WIND ENERGY SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Miguel Sanchez Gomez, Julie K. Lundquist, Petra M. Klein, Tyler M. Bell
Summary: The ISARRA hosted a flight week in July 2018 to demonstrate UAS capabilities in sampling the atmospheric boundary layer. Data from Doppler lidars were used to estimate turbulence dissipation rate, showing large temporal variability and significant influence of measurement volume on retrieved values. This dataset has been openly accessible for further research.
EARTH SYSTEM SCIENCE DATA
(2021)
Article
Geosciences, Multidisciplinary
Tyler M. Bell, Petra M. Klein, Julie K. Lundquist, Sean Waugh
Summary: In July 2018, the International Society for Atmospheric Research using Remotely piloted Aircraft (ISARRA) hosted a flight week to showcase the role remotely piloted aircraft systems (RPASs) can have in filling the atmospheric data gap. Various universities and research institutions deployed instruments to support this campaign.
EARTH SYSTEM SCIENCE DATA
(2021)
Article
Green & Sustainable Science & Technology
Caroline Draxl, Rochelle P. Worsnop, Geng Xia, Yelena Pichugina, Duli Chand, Julie K. Lundquist, Justin Sharp, Garrett Wedam, James M. Wilczak, Larry K. Berg
Summary: Mountains can impact weather downstream by triggering mountain waves when stable air ascends barriers, affecting wind farms. Observations and simulations show that mountain wave characteristics such as speed, wind magnitude, and wavelength are important for forecasters to consider when predicting power output fluctuations. This study highlights the significance of accounting for mountain waves in wind turbine and wind farm design, construction, and forecasting, particularly in complex terrain.
WIND ENERGY SCIENCE
(2021)