Fluid Characteristics of a Savonius VAWT Using Dynamic Mesh
Introduction
Wind turbines fall into two main categories: HAWT horizontal axis wind turbines and VAWT vertical axis wind turbines. HAWT are the most widespread they are generally more efficient than VAWT at least for laminar winds of high speeds. However, they operate poorly in unstable winds or uncertain directions. On the other hand Savonius wind turbine which is classified among the VAWT have a simple construction operate independently of the direction of the wind and starts at low wind speed it was developed and patented by S.J. Savonius in the 1920s according to savonius the best of his rotors had a maximum efficiency of 31% while the maximum efficiency of the prototype was 37%.
Working principle
The Savonius wind turbine is a simple vertical axis device having a shape of half-cylindrical parts attached to the opposite sides of a vertical shaft (for two-bladed arrangement) and operate on the drag force, so it can’t rotate faster than the wind speed. This means that the tip speed ratio is equal to 1 or smaller . As the wind blows into the structure and comes into contact with the opposite faced surfaces (one convex and other concave), two different forces (drag and lift) are exerted on those two surfaces. The basic principle is based on the difference of the drag force between the convex and the concave parts of the rotor blades when they rotate around a vertical shaft. Thus, drag force is the main driving force of the savonius rotor.
Objective
This study aims to computationally investigate the flow characteristic around savonius VAWT and show variation of torque with time and show pressure effect on blades and finally evaluate efficiency of the turbine and we will use Ansys software to do this case
Geometry & Fluid Domain
Mesh
Results
