Investigation of the drag reduction performance of bionic flexible coating

The drag is a crucial factor in reducing the speed of movement and increasing unnecessary energy loss. In this work, inspired by dolphins, five bionic flexible coatings with drag reduction performance were designed and manufactured. First and foremost, the mixed solution, composed of the polydimethylsiloxane and ethyl acetate, was sprayed on aluminum disks with a spray gun, and the bionic flexible coatings were obtained by heating the aluminum disks sprayed with the mixed solution. Afterward, the mechanical properties and surface characteristics of the flexible coatings were characterized. The experimental results for the flexible coatings of drag reduction performance were obtained by using the drag force device. Above all, the parametric study focusing on the flexible coating of the mechanical properties affects the station of flow, which is performed to analyze the impact on drag reduction. Selecting the aluminum disk without any coating as a reference, numerical simulation methods were introduced to explore the drag reduction mechanism of the bionic flexible coating. The results evidence that the drag reduction ratio is 21.6% at the rotation velocity 50 rpm. Under the action of frictional resistance, the coating of elastic deformation caused by the viscoelasticity of the coating like the dolphin skin results in a decrease in frictional resistance of the wall.