Numerical Studies of Flow around a Wind Turbine Equipped with a Flanged-Diffuser Shroud using an Actuator-Disk Model

Unsteady 3-D direct numerical simulations based on the finite-difference method (FDM) were performed for flow fields around a wind turbine equipped with a flanged-diffuser shroud. Generally, it is difficult to numerically simulate the flow around rotating bodies such as the blades of wind turbines because of the unsteady flow generated by moving bodies with complex geometry. Therefore, we have devised an actuator-disk model for a wind turbine for simulating the drag and rotational forces exerted on the fluid by the wind turbine. By incorporating the body forces derived from the actuator-disk model into the external terms in the Navier-Stokes equations, the unsteady flow around a wind turbine can be simulated. The results of numerical simulations were compared with the results from wind tunnel experiments and showed good agreement for the velocity and pressure fields.