Background
The objective of ECOSFARM project is to set-up a generic numerical simulation tool for the evaluation of control strategies, both for offshore wind farms, floating offshore wind farms and tidal turbine farms. This tool, which adopts a precise description of the physics of the flow and the turbines, will be used in the detailed design phase to verify and refine the first rough farms designs calculated in pre-design phase. It will allow for example, for a given turbines disposition to evaluate the control strategies planned, improve them before their integration on real farms at sea, and to confirm the good positioning of the turbines on the installation site.
Scientific advances and innovation
- Increased accuracy regarding the state of the art (eg SOWFA) and highly scalable fluid solver.
- ECOSFARM allows getting a head start on the control brick of fixed or floating tidal turbines farms where there is no precise tool capable of evaluating the control strategy.
- There is also no farm-scale tool for floating wind farm simulation and evaluation of their control strategies. ECOSFARM is a first step in the development of a FOWT tool (medium term goal).
Expected technical and economic impact
- Provide a decision help tool for companies wishing to optimize wind or tidal turbine farm control strategies.
- Promote the consideration of control in wind and tidal research projects.
- ECOSFARM will provide D-ICE a tool to evaluate the controllers they develop before their installation in real conditions at sea and thus to improve the quality of their services. This technological brick will enable them to reinforce their recent position in the wind energy sector and extend it to the tidal turbine sector.
Key project milestones
- Project kick-off - September 2018
- Project end - September 2020
Results
VALIDATION OF WCCH-FAST COUPLING ON NREL 5MW WIND TURBINE CASE
This figure is a comparison of the results obtained using WCCH-FAST coupling with the results of FAST alone. In this aim, we look at 4 gauges positioned along one blade which allow us to monitor Fx, Fy the axial and tangential forces of the blade elements, β the pitch angle of the blade, Ω the rotational speed of the rotor, Trot the torque of the rotor and Pgen the power output of the turbine.
THE PHYSICS THAT CAN BE CAPTURED BY WCCH-FAST
This figure shows the tip and root vortices and some 3D effects that are captured by the WCCH-FAST coupling. On the down left picture, the black arrows show the tip and root vortices that are generated by the coupling. These vortices are provoked by the shear stresses at these locations and are typical of rotors.
On the two other pictures one can observe the 3D effects occurring on the blades. The independence condition between the blade elements invoked in the BEMT does not stand anymore in the case of our Blade Element CFD coupling. This allows a better description of the physics.
APPLICATION TO TWO IN-LINE WIND TURBINES
The experimental case retained for the validation of the WCCH-FAST coupling is the “Blindtest 2” case described and discussed in Pierella et al. 2014. This case presents a configuration involving two in-line wind turbines placed in a wind tunnel.
The figure below presents a comparison of the numerical and experimental deficits of mean axial velocity at locations 1D, 2.5D and 4D in the wake downstream of the second turbine (left), as well as a snapshot of the iso-vorticities in mean axial velocity contour obtained by the simulation (right). The numerical results obtained are in good agreement with the experimental signals, in particular in the far-wake of the wind turbine, outlining the ability of the proposed coupling to model wind farms.
Publications and papers published
Oral communications
- Simulation of an offshore wind turbine using a weakly-compressible cfd solver coupled with a blade element turbine model, ELIE B., Presentation at IOWT 2019
