Revolutionary Performance For Ultra Low Reynolds Number Vehicles, Phase I

An important mission for NASA is the development of revolutionary flight concepts and technology. The development of Micro unmanned air vehicles (Micro-UAVs) and Mars aircraft has received considerable attention in recent years. Unlike conventional aircraft and UAVs, Micro-UAVs and Mars aircraft suffer from operation in an extremely low Reynolds number flight regime. Both Micro-UAVs and Mars aircraft can have operational Reynolds number regimes from 20,000 to 120,000. At these extremely low Reynolds numbers, the aerodynamic flow features are dominated by laminar separation and separation bubble effects, which are the primary source of poor performance in both drag and maximum lift for this class of vehicles. It is proposed to use a robust and powerful active transition fixing technique to eliminate the effects of these large separation bubbles and provide revolutionary performance as of yet unobtainable by this class of ultra low Reynolds number vehicles. By artificially transitioning the flow upstream of the laminar separation bubble, the bubble itself can be eliminated resulting in a greatly reduced drag. The increased resistance to separation of a simple turbulent boundary-layer can pay revolutionary dividends at these very low Reynolds numbers. More »