NUMERICAL SIMULATION STUDY ON BIONIC MUCUS DRAG REDUCTION OF UNDERWATER VEHICLE

The surface characteristics of fish have excellent drag reduction capabilities. Compared with scales, the mucus secreted by the fish body surface has even better results. In this paper, the FENE-P constitutive model and the mixture multiphase flow model are used to simulate the drag reduction effect of the underwater vehicle secreting mucus (viscoelastic fluid) to form a mucous membrane on the outer surface from the perspective of bionics. The simulation results show that the drag reduction rate of the mucous membrane can reach about 17%. The increase in the thickness of the boundary layer caused by the mucus and the backward movement of the separation point are the main reasons for the decrease in resistance. The turbulence statistics of the boundary layer of the aircraft and the Reynolds stress are also compared, and the influence of the parameter change on the drag coefficient is obtained. The maximum drag reduction rate occurs when the viscosity ratio is 0.8, the maximum molecular stretch length is 80, and the Weissenberg number is 20, which provides a new method for drag reduction of underwater vehicles.