Study of the effect of the AFC on the wind turbine blade aerodynamics

The main objective of this Mater Thesis is to study which is the effect of using Active Flow Control techniques on the aerodynamics of a wind turbine aerofoil. The study is performed over a NACA 4418 aerofoil, a common blade’s root aerofoil with a quite simple shape to avoid strange interactions between upper and lower generated vortices. The simulations are performed at low Reynolds numbers due to the limited computational resources and time. The cases studied are performed at a fixed 10o angle of attack and the parameters changed to study their effect are slot location, jet angle, jet velocity ratio and two different techniques, suction and injection. The mesh is generated via a MATLAB semi-automatic script and with GMSH. Then, the mesh obtained is simulated using OpenFoam integrated solvers. The results are analysed using ParaView and self – developed MATLAB scripts. The idea of having a semi – automatic mesh generator is to have a really quick tool to vary the aerofoil used or the angle of attack and have the new mesh in few seconds. The work process is based on simulating a base case to get the aerodynamics of the aerofoil without AFC usage, then, taking the results from base case, place the slot and define the AFC to be used and see how much does the AFC usage improve the aerodynamics of the aerofoil and which is the effect on the trailing edge’s vortex shedding. The results showed that suction is the easiest AFC of the two studied to be simulated, as there are no values which can cause strange phenomenon. On the other hand, the usage of injection needs to be carefully defined to avoid a premature detachment of the boundary layer and the consequences derived from it.