Study of Airfoils for the Unique Micro Wind Turbine Blade

Abstract

An airfoil of insect’s wing is completely different from the conventional streamlining airfoil, and it has very thin corrugated cross section. As you can see from the flight of insects, their wings are used in the low speed region, functioning in a speed region different to the ones in which streamlining airfoil is used. Studies on the aerodynamic characteristics of the corrugated wing in the low speed region are very limited, with many aspects still remaining unknown.In order to clarify aerodynamic characteristics of corrugated airfoil in the low speed region, we have developed our own system composed of micro three-component balance and swirl-type experimental water channel, and investigated the aerodynamic characteristics of the corrugated airfoil and curved plate having smooth cross section in the low speed regions (Re=7,000 and 11,000). This investigation revealed that, in the low speed regions the aerodynamic characteristics of the corrugated airfoil was equivalent to or superior than those of the curved plate, and it was also found that the aerodynamic characteristics of the curved plate were very susceptible to the changes in Reynolds number whereas those of the corrugated wing were insusceptible to the changes. In the past, a small wind turbine has not been paid much attention as a source of alternative energy because of its low availably in low wind speed region and of its difficulty in handling it. All of these issues inherent in the small wind turbine will be solved by adopting the corrugated wing in the wind turbine. All of these findings from our investigation are reported in this paper.