Numerical studies of flows around a wind turbine equipped with flanged-diffuser shroud by using an actuator-disc model

Unsteady 3-D direct numerical simulations based on the finite-difference method (FDM) are carried out for flow fields around a wind turbine equipped with a flanged diffuser shroud. Generally, it is difficult to simulate numerically the flow around rotational bodies like rotors of wind turbines, because of unsteadiness due to a moving body and complex geometry. Therefore, we have devised an actuator-disc model for a wind turbine for simulating the resistance and rotational forces on fluid. Introduced those volume forces devised from the actuator-disc model into the external terms in N-S equations, the unsteady flow around a wind turbine can be simulated. The results of numerical simulations are compared with the wind tunnel tests and show a good agreement for the velocity and pressure fields.