Research Note — RES‑007 · Computational Fluid Dynamics

CFD of a Savonius Vertical‑Axis Wind Turbine

Computational Fluid Dynamics · Iran University of Science and Technology · ANSYS Fluent

A 2D CFD study of the turbulent flow field around a rotating Savonius vertical‑axis wind turbine (VAWT), aimed at capturing the vortex shedding and wake structure that drive the turbine's torque. The rotor was modeled with a Moving Reference Frame (MRF) inside a larger stationary domain, and turbulence was closed with the k‑ω model.

Part 1

Computational Domain & Mesh

• Built a rectangular far‑field domain with a circular rotating sub‑domain (MRF zone) enclosing the Savonius rotor
• Generated an unstructured triangular mesh, refined sharply near the blade walls to resolve the boundary layer and shed vortices
• Solved the flow as turbulent, unsteady, incompressible, using the k‑ω turbulence model with the rotor zone rotating via the Moving Reference Frame method

Computational domain (far-field + MRF zone) Mesh overview — refined around rotor Blade wall — boundary-layer mesh detail

Part 2

Turbulence & Wake Structure

• Tracked vortex shedding from the advancing (upwind) blade as it interacts with the returning blade
• Visualized the downwind wake, where the shed vortices merge into a narrow, high‑turbulence jet behind the rotor
• Contours show turbulence kinetic energy across the domain, highlighting how blade rotation continuously regenerates the wake structure

Vortex shedding around the rotor Downwind wake behind the turbine