The Work Plan consists of 2 technical Work Packages. WP1 and WP2 are focused on experiments and calculations respectively whereas WP3 ensures good cooperation with other IEA Tasks.
In WP1 and WP2 several calculations are performed. It is then important to know that the present consortium covers the entire spectrum of design models ranging from efficient low fidelity models as used in industry to high fidelity computational extensive models used by research institutes with a variety of intermediate models in between. In this way, a very good insight is obtained on how different models cope with the design of large wind turbines under real inflow.
The main goal of WP1 is to share experiences in the specialistic field of detailed aerodynamic measurements. Several new aerodynamic experiments are currently being initiated. This is true in Denmark, France, Germany, Italy, Netherlands, Switzerland, and the USA.
In the WP the experimental parties learn from each other about methods and techniques which work successfully and what should be prevented so that they all improve the quality of the experiments. Moreover, the measurement results will be shared with the consortium so that the theoretical partners get first-hand information from these unique new data. For example, unsteady pressure distribution at special events (standstill, heavy gusts) will provide much insight into the aerodynamics at such events and form the inspiration for theory development. Measurements from at least the DanAero experiment will be simulated under turbulent conditions.
Thereto it should be known that the first three phases of IEA Task 29 considered measurements at non-turbulent wind tunnel conditions. In the final phase, DanAero measurements in the field were simulated but mostly under steady time-averaged conditions. Obviously in cases of turbulent inflow a statistical evaluation e.g. an evaluation based on mean values as carried out in Task 29 is useful but it is equally important to analyze the development of forces over time. It was found that modeling the aerodynamic response at turbulent conditions leads to several additional complications which have a large impact on the loads and which are not or are poorly understood yet. Moreover, a major research effort is needed to ensure a consistent comparison procedure between low and high-fidelity models which is explained below and which forms part of WP2.
An even larger challenge, which forms the subject of WP1.2 lies in a consistent comparison between calculations and measurements. The wind speed in the DanAero experiment is measured at a mast some distance away from the turbine which may not form sufficient input for a comparison between calculations and measurements on a time series basis.
It is anticipated that 2 rounds of calculations are carried out where every round will consist of several iterations. Within IEA Task 29 much experience has been gained with modeling the Danaero turbine already so that a fully tested model description is available.
The first round is planned to start in August 2021 and lasts until October 2022.