DTU Wind and DHI have successfully developed, installed and tested the world’s largest open-jet wind generator for floating wind tests – a major milestone in advancing the physical testing of floating offshore wind turbines.

The wind generator can blow up to five metres per second, corresponding to 42 m/s with a model scale of 1:70 – which equals the speeds of a full-strength hurricane. It is therefore believed to be the world’s most powerful for floating wind tests. Combined with 3D waves with directional spreading in DHI’s ocean basin, the facility enables comprehensive testing of floating wind turbines under operational and extreme conditions.

The wind generator is a key deliverable in the FloatLab research project and will allow the team to perform test campaigns that simulate extreme offshore conditions using realistic wind and wave interaction. The FloatLab project aims to ultimately reduce risks and validate engineering models used for turbine and floating foundation design in the offshore wind sector.

‘In our spring test campaign, we have documented its performance and applied it to test a design variant of Stiesdal Offshores TetraSub concept,’ says Henrik Bredmose, Professor at DTU Wind. ‘Each of the 25 fans operates as part of a synchronised system. Very much like voices in a choir, singing a very coordinated melody,’ says Henrik Bredmose. ‘The fans replicate the turbulent inflow that turbines experience offshore. So now, we can physically recreate turbulence in a controlled lab setting for floating wind.’ 

In the tests, the project team uses a scaled version of the IEA Wind 22-megawatt turbine, mounted on a variant of the Stiesdal TetraSub floating foundation. It is already built and installed at DHI’s wave basin facility in Hørsholm, Denmark. 

Measurements of the tests will be connected directly to calculation models in a digital twin setup. The aero-hydro-servo-elastic response of the floater and turbine in wind and waves can then be simulated and studied, potentially improving accuracy and reducing risk. 

‘With the wind generator now in operation, we can replicate offshore wind and wave conditions more realistically than ever before,’ says Pietro Danilo Tomaselli, Senior Hydraulic Engineer and Head of FloatLab activities at DHI. ‘This gives DHI and DTU Wind a unique opportunity to optimise floater designs, improve turbine control systems, and validate engineering models, ultimately making floating wind a more reliable and cost-effective solution for the green transition.'