Wing Efficiency Enhancement at Low Reynolds Number

The aerodynamic performance of wings degrades severely at low Reynolds number; lift often becomes non-linear, while drag increases significantly, caused by large extents of separation. Consequently, a non-conventional wing design approach is implemented to assess its ability to enhance performance. The design methodology is that of wing segmentation, where the wing is divided into spanwise panels that can be separated, thereby yielding small gaps between the panels. A moderate aspect ratio wing comprised of four separate wing panels was manufactured and wind tunnel tested through a Re range from 40,000 to 80,000. Force balance data and surface flow visualization were used to characterize performance. The results indicate that segmentation is effective in significantly augmenting efficiency at Reynolds numbers at which the fused wing (i.e., no gaps) shows large extents of open separation. Drag is greatly reduced, while lift is increased, and stall is delayed. The benefit of segmentation was noted to diminish at higher Re where the fused wing's performance improves markedly. Wing segmentation could find application in micro-unmanned-aerial-vehicle and drone design. Further study would entail the effects of AR and the number of spanwise panels on performance.