Fundamental Study on Improvement of Performance of Wells Turbine Blade

Abstract

In the present paper the attention is focused on the effect of the dimples on the stall characteristics and aerodynamic sound radiated from two-dimensional airfoil. In general, two-dimensional blade is used as the airfoil of Wells turbine. We measured the lift force acted on the airfoil and aerodynamic sound. The dimples were effective to improve the stall characteristics. As the dimple diameter and number of dimples increased, the broadband noise at higher frequency component increased slightly compared with normal airfoil. The dimples were not effective to reduce the broadband noise radiated from airfoil. In contrast, the dimples were effective to reduce the discrete tone noise radiated from airfoil. This noise depended on the geometry, position and number of dimples. The suitable geometry, position and number of dimples were discussed to improve the stall characteristics and reduction of aerodynamic sound.