Wind turbine simulations with OpenFOAM

Abstract

To test different turbine designs it is desirable to have a model where one can switch between different designs and getting results with sufficient accuracy. With this in mind two CFD models for turbines are created. A simple and easy 2D wind turbine model is created using an actuator disk imposing a body force and with an impermeable hub. A more advanced model is created by fully resolve the flow around the turbine geometry and using arbitrary mesh interface (AMI) as a sliding boundary between the rotational and stationary mesh. Simulations done with OpenFOAM of both models are compared with wind tunnel measurements. The results from the simulations of the actuator disk reveals that the model is mesh dependent, but with a carefully chosen mesh with low y+ values and no wall-functions the wake is well reproduced on a qualitative level. The simulations using the advanced model had to be made with a coarser mesh than intended due to limited computational resources. Still, the results are promising with good wake reproduction and well estimated thrust coefficient, and a power coefficient with an estimated error of 19% being dependent on mesh resolution around the blades.