Research on the Drag Reduction Performance of Bionic Micro-gradient Surfaces

Abstract Long range and high speed are important performance indicators for modern naval equipment such as submarines and ships. Taking the special shield scale structure of shark epidermis as the research object, models of riblets, discontinuous riblets, equal-gradient riblets and shark-like micro-gradient riblets were established, and their effects on flow field characteristics were analyzed. Compared with smooth surfaces, the bionic micro-gradient surface had a maximum drag reduction rate of 9.93% under the combined action of streamwise vortices and spanwise secondary vortices, and maintained a good drag reduction effect over a wide speed range. The bionic micro-gradient surface provides a potential reference for underwater mechanical drag reduction design.