Reduction of skin-friction in large-scale turbulent flows using superhydrophobic surfaces

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Skin-friction force opposes the motion of a fluid over a solid surface. It forms almost all the opposing force in transportation of oil and gas through pipelines and also a substantial portion of the drag force acting on aircraft and marine vehicles. The ubiquitous resistance of skin-friction in the transportation industry and its direct impact on the annual fuel consumption and emission of pollutants have promoted research on different mitigation methods.*Advances in micro/nano fabrication have introduced synthetic superhydrophobic surface as a method with significant potential for reduction of skin-friction in liquid flows. A superhydrophobic surface is formed by micro/nanoscale roughness covered by a thin hydrophobic coating which prevents liquid from entering the cavities. This combination results in formation of liquid-air interface with negligible friction allowing the liquid to freely slip. The performance of superhydrophobic surfaces in turbulent flows has been observed to be different than the laminar regime indicating a complex mechanism depending on the flow regime.*The objective of the proposed research program is to investigate the application of superhydrophobic surfaces for reduction of skin-friction in large-scale turbulent flows relevant to industrial applications. The research will include a detailed characterization of the turbulent boundary layer at the immediate vicinity of the surface in order to identify the mechanism of skin-friction reduction. Development of models and superhydrophobic surfaces with maximum reduction of skin-friction and longevity of the air-liquid interface will be pursued.*The proposed research will provide the practical guidelines for long-term goal of reduction of skin-friction and consequently development of efficient and environmentally friendly pipelines of oil, petroleum products, and carbon dioxide across Canada.