Bioinspired micro/nanostructured surfaces for oil drag reduction in closed channel flow

Living nature contains amazing structures and materials which provide inspiration for bioinspired solutions that can solve many of mankind's greatest challenges. Two such challenges include reducing fluid drag and promoting self-cleaning. With inspiration from promising flora and fauna, a systematic study has been conducted using a combination of actual and replica samples. These include rice leaf, butterfly wing, fish scale, and shark skin samples, as well as laser etched riblets. In order to mimic properties from actual rice leaves, select replica and riblet samples received a nanostructured coating. Drag is determined by pressure drop measurements from sample lined rectangular closed channels with laminar oil flow. Oleophilic surfaces with appropriate micro/nanostructured surfaces may allow the formation of a thin oil film believed to reduce drag. A conceptual model is presented describing the role of surface structures allowing the formation of such a drag reducing thin oil film.