Analysis of Shark Skin Riblet Surfaces for Fluid Drag Reduction in Turbulent Flow Regime

: The integument of fast swimming shark exhibits riblet inspired micro- structured surfaces oriented in the path of flow that will help to make lesser the wall drag in the tempestuous-flow system (turbulent flow). Design have been made for study and utilization, that has been recreate and refine as same as of the shark-skin riblets, presuming an extreme drag depletion of nearly 10% (percent). Mechanism of fluid drag in tempestuous flow and riblet drag depletion theories from experiments and simulations are examined. An examination of riblet intrepratation are discussed and the stellar riblet sizes are defined. An assessment of studies experimenting with riblets-topped shark scale replicas is also discussed. A method for preferring stellar riblet dimensions based on fluid-flow attributes is briefed and current manufacturing approaches are summarized. Due to the existence of little amounts of mucus/booger membranes on the integument of the shark, it is presumed that the constrained application of aqua phobic materials will recast the flow field around the riblets in some way favorable to the goals of augmented drag depletion

Preparation and fluid drag reduction properties of superhydrophobic paper-based films comprising carbon nanotubes and fluoropolymers

Carbon nanotubes (CNTs) were successfully prepared using chemical vapor deposition method on nickel-coated silicon substrates. The CNTs were then modified to obtain functionalized ends. Afterward, acrylate polymers were successfully grafted on the surface of CNTs by atom transfer radical polymerization method. The synthesis process was optimized by studying the surface properties of the composite films. It revealed the existence of chemical bonding between CNTs and polymers. The introduction of CNTs into polymers could improve the water resistance of films. Micro/nano and papillary structures similar to that of lotus leaf were obtained when the polymer matrix was partly etched. The excellent fluid drag reduction performances of film surfaces were expected to be applied in microfluid devices and packaging field.