Shark Skin Surfaces for Fluid-Drag Reduction in Turbulent Flows

Nature has created ways of reducing drag inFluid flow application fluid flowFluid flow, evident in the efficient movement of fish, dolphins, and sharks. The mucus secreted by fish reduces drag as they move through water, protects the fish from abrasion by making the fish slide across objects rather than scrape, and prevents disease by making the surface of the fish difficult for microscopic organisms to adhere to, minimizing biofoulingBiofouling (Shephard in Rev Fish Biol Fish 4:401–429, 1994). Applications of drag reducing polymers has been long known.