Two-Blade Savonius Wind Turbine: 2-D

Savonius (Two-Blade) Wind Turbine (2D) — ANSYS Fluent CFD Simulation

Description

This project presents a 2D CFD simulation of a Savonius wind turbine using ANSYS Fluent. The Savonius turbine is a type of vertical axis wind turbine (VAWT) used to generate electricity from wind, with curved blades mounted on a vertically positioned rotor. The most important advantage of vertical turbines is that they need no adjustment to the wind direction and can be used at low altitudes. This project simulates the airflow around a two-blade Savonius rotor to illustrate the pressure and velocity distribution and to animate the fluid motion behind the turbine.

Methodology

The geometry is produced in Design Modeler: two blades of 350 mm diameter and 25 mm thickness placed in a rotating circle of 1000 mm diameter, surrounded by an 8000 mm × 4000 mm rectangular domain. The model is meshed in ANSYS Meshing with 58,468 elements, and the transient solver is enabled to accompany the Mesh Motion option. Air enters the fluid domain at the inlet with a velocity of 10 m/s while the turbine rotates at a constant angular velocity of 40 rpm. The Mesh Motion option defines the rotating motion of the blades, and the SST k-omega model solves the turbulent flow equations, chosen for its ability to capture the flow patterns both near and far from the blade surfaces.

Analysis

After the solution, 2D contours of pressure, velocity, and streamlines are obtained, showing how the fluid changes as it moves through the turbine blades. The results reveal distinctly different pressure and velocity distributions on the inner and outer blades. The flow enters at 10 m/s, and after colliding with the inner blade a large pressure increase occurs, so the velocity magnitude drops and reaches zero at the stagnation point — which can cause an unwanted negative torque. The outer blade, by contrast, experiences a high-velocity flow across its back that tends to push it clockwise, driving the rotation. By the end of this project, you'll be able to set up a transient 2D Mesh Motion simulation of a Savonius VAWT, define a rotating zone for the blades with the SST k-omega model, and interpret the pressure and velocity contours that reveal how the inner and outer blades contribute to the turbine's torque.