IEA Wind TCP

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 where it should be realized that a consistent comparison procedure between calculations (mutually) and between calculations and measurements will require much attention.

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.

WP2 is defined around turbulent calculations on a large-scale 15 MW wind turbine. Thereto a large variety of aerodynamic and aero-elastic models are available in the consortium. In this way, a very good insight is obtained into how different models cope with the design of 15MW wind turbines under real inflow and what the most important uncertainties are. These insights can be used in WP1 to define experiments that can answer these questions, even if the experiment is done on a smaller scale.

As an example calculations at parked storm conditions on a 15 MW RWT might lead to loads that depend heavily on the dynamic stall model used: one model may predict a stable solution, and another may predict an unstable solution leading to failure of the blades. If this becomes true, special attention is paid to the design of an experiment that measures dynamic stall effects at standstill. Another example is that the torsional flexibility of large blades might lead to unsteady aerodynamic effects. If this becomes true special attention needs to be paid to measure such effects.

It is noted that the setup and character of the calculations on the 15 MW RWT are very similar to the calculations in WP1. However, the present calculations are performed on the 15 MW RWT without measurements whereas WP1 carries out calculations on the DanAero turbine which are not only compared mutually but also with measurements. It should be noted that for turbulent calculations attention needs to be paid to a consistent comparison procedure between low and high-fidelity models under turbulent conditions.

The task starts with preparatory calculations  which aim to establish the aerodynamic reference, i.e. a correct aerodynamic input so that each model will simulate the 15MW RWT in the follow-up tasks without trivial input errors. Thereto aerodynamic simulations will be carried out under relatively simple conditions, e.g. uniform steady flow, prescribed shear, prescribed gusts, etc.

Results will be compared until confidence is obtained on the correct input. Moreover, an aero-elastic Benchmark will be carried out which aims to gain confidence in the aero-elastic input. Thereto several aero-elastic properties (e.g. Eigen frequencies modes etc.) are compared. It is then expected that the turbulent calculations on the 15 MW RWT will start in 2023.

In WP3 the main achievements from Task 47 are communicated to other IEA Wind Tasks which have connections to aerodynamics and vice versa. It is anticipated that in the present IEA Task many participants will be active in other IEA Tasks and the most effective way of communication is seen to be the appointment of these participants as contact persons for other Tasks.