KSEF RDE: Development of Micro-Actuated Artificial Mucus Layer for Drag Management and Flow Control for Unmanned Micro Vehicles

Abstract Flow control has been a long-standing interest for various engineering applications, particularly in the areas of AUV (autonomous underwater vehicle) and UAV (unmanned aerial vehicle) technology. Sustainable drag reduction schemes capable of operating in a wide range of flow conditions can significantly improve performance and efficiency. Flow control can also be used to maneuver an air/ocean vehicle with high agility, as is often done in nature without the use of discrete control surfaces. Current drag manipulation techniques have achieved limited success and few practical applications. Marine animals, on the other hand, have effectively solved the problem. For instance, the flow of fluid around a shark during its high-speed maneuvers remains attached. It is believed that a thin mucous layer provides fish with this extraordinary ability. In this regard, we propose to explore a new biologically inspired drag management mechanism. Project goal is to develop a microscale artificial mucus layer (-50um thick) actuated by micro-actuators fabricated from new intelligent materials to generate a traverse traveling wave within "mucous" layer. Consequently, wave will induce a small amplitude (10-50 um) motion in the viscous sub layer located directly above wall (-50 um thick). The net effect is to create a buffer layer between momentum-carrying outer flow and drag-generating solid surface, which controls the flux of momentum exchange. By varying the amplitude of the traveling wave, one can expect to change the thickness of the buffer layer and, therefore, to manage the drag exerted on the surface. The primary tasks of the proposed work are (1) develop a novel proof-of-concept flow control surface and demonstrate manufacturing feasibility, (2) conduct a preliminary performance study of efficacy, (3) develop and demonstrate a controllable flow manipulation scheme using the proposed surface, and (4) provide an experimental model for more detailed studies on the fundamental physics and further improvement.