Abstracted/indexed

The publication of the Reference Open-Source Controller (ROSCO) provides a controller and generic controller tuning process to the wind energy research community that can perform comparably or better than existing reference wind turbine controllers and includes features that are consistent with industry standards. Notably, ROSCO provides the first known open-source controller with features that specifically address floating offshore wind turbine control.

Wind turbines are frequently placed in forests. We investigate the potential of using satellites to characterise the land surface for wind flow modelling. Maps of forest properties are generated from satellite data and converted to flow modelling maps. Validation is carried out at ten sites. Using the novel satellite-based maps leads to lower errors of the power density than land cover databases, which demonstrates the value of using satellite-based land cover maps for flow modelling.

A new high-resolution data set (NORA3) is validated for offshore wind power purposes for the North Sea and Norwegian Sea. The purpose of the validation is to ensure that NORA3 can act as a planning tool for future offshore wind power installations in the area of concern. The general conclusion of the validation is that NORA3 is well suited for wind power estimates, but gives slightly conservative estimates on the offshore wind metrics.

In RANS-CFD, e^N-based method showed its superiority over local correlation-based transition models (LCTM) coupled with the SST turbulence model for predicting transition behavior at high-Reynolds number flows (3–15 million). In this study, we evaluated performance of two LCTMs coupled with SA turbulence model. As a result, the SA-based two-equation transition model showed a comparable performance with the e^N-based method and better glide ratio (L / D) predictions than the SST-based model.

Wind farm layout optimization is an essential part of wind farm design. In this paper, we present different methods to determine the number of turbines in a wind farm, as well as their placement. Also in this paper we explore the effect that the objective function has on the wind farm design, and found that wind farm layout is highly sensitive to the objective. The optimal number of turbines can vary greatly, from 15–54 for the cases in this paper, depending on the metric that is optimized.

The study aims for a computationally inexpensive model describing the wind deficit behind a wind energy converter analytically using some assumptions and basic governing equations of the atmosphere. Thus, the influence of different atmospheric conditions onto the wake development can be studied in the future which is important e.g. in wind park planning. The model is compared to conventional empirical wake models and in-situ UAS measurements captured along the wake at hub height.

The design of a ducted wind turbine was optimized to maximize the power per total cross-sectional area of the device. The associated power coefficient was 0.69, which is significantly greater than that obtainable from an open rotor turbine. Furthermore, it was shown that there is an optimal duct length, which is 15 % of the rotor diameter.

Turbine-mounted lidars performing inflow scans can be used to optimise wind turbine performance and extend their lifetime. This paper introduces a new method to extract wind inflow information from a turbine-mounted scanning SpinnerLidar based on Proper Orthogonal Decomposition. This method offers a balance between simple reconstruction methods and complicated physics-based solvers. The results show that the model can be used for lidar assisted control, loads validation and turbulence studies.

Floating wind turbines undergoes complex aerodynamic phenomena that are not completely understood. This paper presents an scale-model wind tunnel experiment about the investigated the unsteady aerodynamics of floating turbines with a radically different approach than previous experiments. The problem was studied under different aspects, from airfoil aerodynamics to wake.

Wind turbines are often clustered within wind farms. A consequence is that some wind turbines may be exposed to the wakes of other turbines, which reduces their lifetime due to the wake turbulence. Knowledge of the wake is thus important, and we carried out wind tunnel experiments to investigate the wakes. We show how models that describe wakes of bluff bodies can help to improve the understanding of wind turbine wakes and wind turbine wake models, particularly by including a virtual origin.

Floating wind is the key technology to harvest the abundant wind energy resource of deep waters. This research introduces a new way of controlling the wind turbine to better deal with the action of waves. The turbine is made aware of the incoming waves and the information is exploited to enhance power production.

Wind turbines extract momentum from atmospheric flow and convert that to electricity. This study explores recovery processes in wind farms that replenish the momentum so that wind farms can continue to function. Experiments with a numerical model show that momentum transport by turbulent eddies from above the wind turbines is the major contributor to recovery except for strong wind conditions and high wind turbine density where horizontal advection can also play a major role.

This paper introduces the numerical models of two 15MW Floating Offshore Wind Turbines (FOWTs) WindCrete and Activefloat. WindCrete is a spar floating platform designed by Universitat Politècnica de Catalunya, while the Activefloat is a semi-submersible platform designed by Esteyco. The floaters are designed within the Horizon 2020 project COREWIND. Afterwards, the responses of both models to wind and second order waves are analyzed with an emphasis on the effect of second order waves.

This study investigates systematic, seasonal biases in the long-term correction of short-term wind measurements (< 1 year). Two popular Measure-Correlate-Predict (MCP) methods yield remarkably different results. Six reanalysis data sets serve as long-term data. Besides experimental results, theoretical findings are presented which link the mechanics of the methods and the properties of the reanalysis data sets to the observations. Finally, recommendations for wind park planners are derived.

We carry out a probabilistic calibration of the Dynamic Wake Meandering (DWM) model using high spatial and temporal resolution nacelle-based lidar measurements of the wake flow field. The experimental data were collected as part of the Small Wind Farm Technology (SWiFT) experiment in Texas. The analysis includes both the velocity deficit, wake-added turbulence, and wake meandering features under various inflow wind and atmospheric stability conditions.

Active trailing edge flaps can potentially enable further increases in wind turbine sizes without the disproportionate increase in loads, thus reducing the cost of wind energy even further. Extreme loads and critical deflections of the turbine blade are design driving issues that can effectively be reduced by flaps. This paper considers the flap hinge moment as an input sensor for a flap controller that reduces extreme loads and critical deflections of the blade in turbulent wind conditions.

When ice forms on wind turbine blades, the smooth surface of the blade becomes rough which changes its aerodynamic performance. So, it is very important to know how to simulate this rough surface since most CFD simulations depend on assuming a smooth surface. This article compares different mathematical models specialized in simulating rough surfaces with results of real ice profiles. The study presents the most accurate model and recommends using it in future airflow simulation of iced blades.

Offshore wind turbines are huge, with rotor blades soon to extend up to nearly 300 meters. Accurate modeling of winds across these heights is crucial for accurate estimates of energy production. However, we lack sufficient observations at these heights but have plenty of near-surface observations. Here we show that a basic machine learning model can provide very accurate estimates of winds in this area, and much better than conventional techniques.

The objective of the paper is to develop a data-driven output constrained individual pitch control approach, which will not only mitigate the blade loads but also reduce the pitch activities. This will lead to an economically viable load control strategy. The proposed control strategy shows promising results of load reduction in the wake-rotor overlapping and turbulent wind conditions.