Drag reduction over a low reynolds number cavity surface
A butterfly uses an efficient and complex flight mechanism comprised of multiple interacting flow control devices that include flexible, micro-geometrically surface patterned, scaled wings. The following research ascertains if any aerodynamic advantages arise from the formation of vortices in between successive rows of scales on a butterfly wing. The computational model consists of an embedded cavity within a Couette flow with the flat plate moving transversally over the cavity. The effects of cavity geometry and Reynolds number are analyzed separately. The model is simulated in ANSYS FLUENT and provides qualitative insight into the interaction between the scales and the boundary layer. Preliminary results indicate that vortices form within the cavity and contribute to a net partial slip condition. Further, the embedded cavities contribute to a net reduction in the drag coefficient that varies with Reynolds number and cavity geometry.