Darrieus Wind Turbine: 6-DOF

Description

This project uses ANSYS Fluent to simulate a Darrieus vertical axis wind turbine (VAWT) with the Dynamic Mesh 6DOF method, a core application of the dynamic mesh module for modeling rotation driven by fluid forces rather than a prescribed motion. The turbine's curved blades keep them in tension at high rotational speeds, and a helical blade arrangement helps distribute torque evenly across the revolution, reducing pulsation. In this case, a 6-blade Darrieus turbine is exposed to wind at 23 m/s, with turbine rotation resolved based on the moment generated by the flow itself.

Methodology

The 3D domain is built in DesignModeler, consisting of a flow domain and a body-of-influence region around the turbine, with a velocity inlet, pressure outlet, and ground wall boundary. The domain is meshed in ANSYS Meshing using an unstructured grid of 2,966,928 elements and 720,300 nodes. Turbine rotation is captured using the Dynamic Mesh 6DOF method, allowing the blades to rotate in response to the aerodynamic moment acting on them, rather than a fixed prescribed rotational speed.

Conclusion

Results show clear turbine rotation driven by the flow, with velocity contours revealing vortices — including Von Kármán vortex shedding — generated by the interaction between the flow and the rotating blades. Pressure contours show the highest pressure gradient at the blade leading edge, consistent with the flow velocity dropping to zero at that point. Streamline vectors resolve the wake region flow quality, a key challenge in this type of aerodynamic simulation, while the turbulence contour accurately captures the resulting turbulent structures.