Accurate modelling of wind turbine wakes is critical for optimizing wind farm performance, but the complexity of wake interactions poses significant challenges. This study presents a two-phase blind test campaign, part of the Horizon Europe TWEET-IE project, designed to benchmark numerical models and investigate wake control strategies using wind tunnel experiments. Conducted with tandem wind turbine models at the Technical University of Munich and the National Technical University of Athens, the tests include inflow, load, power, and wake velocity measurements under controlled conditions. Phase I serves as an open-data benchmarking exercise for a baseline scenario without wake control, while Phase II introduces active individual blade pitch control to the upstream turbine, challenging participants to simulate advanced wake dynamics. This paper reviews Phase I results and details the experimental framework for Phase II, providing a foundation for advancing wake modelling and control in wind energy research.

Wind turbine wake and modelling is crucial to optimizing future wind farm layouts and hence reducing the cost of energy. This paper presents the first phase of a blind test on modelling controlled and uncontrolled wind turbine wakes. The blind test is based on wind tunnel experiments of two model scale wind turbines (D = 1.1 m) one downstream of the other. The exercise is split into two phases and the first one is presented here, where participants are invited to simulate the baseline case, in which both turbines are aligned with the flow and there is no control on the either turbine. The objective of this phase is to ensure all participants can benchmark their numerical approach against a baseline open data set, where no wake control is applied. Experimental measurements include inflow velocity, turbine power and loads for a range of tip speed ratios. In the second phase, not presented here, the wake of the upstream turbine will be controlled and the performance of the downstream one will be recorded. This will be a blind test with the data not released prior to submissions. The present paper gives an overview of the initial, open benchmark case, including its objectives, methodology and experimental results.