I-Corps: Engineered bio-inspired surface for passive flow control

Texas Tech University, Lubbock TX

Investigators

Abstract

The broader impact/commercial potential of this I-Corps project stems from the fact that the micro-textured surface proposed in this project can reduce drag - the force experienced by an object moving through air or water. Ground transportation vehicles, airplanes, drones, underwater vessels, wind turbines, and HVAC fans all experience the adverse effects of drag in terms of increased fuel/electricity consumption, increased greenhouse gas emissions, and reduced energy production. Potential efficiency gains using the proposed technology can save numerous industries significant energy costs, reduce greenhouse gas emissions, and solve a multitude of problems associated with aerodynamic/hydrodynamic inefficiencies. For example, a 5% increase in efficiency due to drag reduction translates to $5 billion in fuel savings for the trucking industry and the equivalent energy production of an additional 2000 wind turbines per year for the wind energy industry. Micro-textured surfaces for passive flow control presents a unique opportunity in enhancing efficiency in that it can be designed for optimal performance depending on the application to yield the highest possible efficiency gains. This I-Corps project features a micro-structured coating inspired by shark-skin, which passively modifies the flow close to the surface of an object resulting in drag reduction both in air and water applications. Experimental results performed using the section of a wind turbine airfoil in a water tunnel showed that the proposed micro-structured film, made out of a commercially available polyurethane, can delay and reduce the size of the separation bubble, the phenomenon responsible for increased drag, by 60%. The effect of this reduction on drag was also confirmed in wind tunnel experiments. Reductions of up to 30% and 13% were recorded over an airfoil and a cylinder, respectively. Additionally, enhancements of up to 45% in lift generated by an airfoil was measured when the micro-structured coating was applied to the surface. The ability of the proposed technology to increase fuel and conversion efficiencies will have a transformative impact in many industries including ground transportation, aerospace, and wind energy. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.