Abstract
The present study focuses on the wings of dragonfly, by which dragonfly has sluggish speed of flight and high capability of flight. Actually the structure of dragonfly wings is not the streamline but the asperity. In the this study PIV is used to measure to flow velocity around the section model of the dragonfly wings, as to extract the effect of the surface structure on boundary layer. In addition, the section of the actual wing is quantitatively analyzed by wavelet transform. Three section models of wings, a streamline model, and the flat model are used. Based on the wavelet transform, it is found that the asperity of the dragonfly wings consists of large- and small-scale wave. From PIV, the asperity of the leading edge has strong effects on the flow and control the boundary layer.
