Numerical simulation on drag reduction characteristics of concave corner microstructure of springtail cuticle

Underwater drag reduction technology is one of the key ways to break through the ocean-going problem, and the bionic drag reduction is very promising in many types of drag reduction method. The bionic drag reduction is using the gasliquid interface slip effect, while the film is very unstable, leading to drag reduction function failure. The concave corner microstructure of springtail cuticle can make the air retention, which has very important significance to solve the problem of instability of gas film. In this paper, a simplified model is established by referring to the concave corner microstructures of springtail cuticle. The k-ε turbulence model is coupled with VOF method is used to establish a simulation model. The simulation results show that: with the increase in free shear area ratio, the drag reduction rate of the microstructure increases; the drag reduction rate of different microstructure is slightly different, but it is mainly related to the free shear area ratio.