Analysis of energy-saving and drag-reduction characteristics of bionic non-smooth jet coupling structures

Abstract To improve the speed of the vehicle, extend its range, and reduce energy consumption, a bionic non-smooth jet coupling structure model was designed based on the jet drag reduction mechanism of shark gills. The SST k-ω turbulence model was used for numerical simulation of the coupling structure surface. By varying the spacing distance of the jet holes, the variation laws of wall viscous drag, pressure drag, drag reduction rate, and energy-saving rate were analyzed. The action mechanisms of compressive stress, velocity field, vortex structure, shear stress, and turbulent kinetic energy on the drag-reducing surface were clarified, and the energy-saving and drag-reduction mechanisms of the non-smooth jet coupling structure surface were revealed. The results show that under a flow field of 20 m s −1 , the non-smooth jet coupling structure achieves a maximum drag reduction rate of 11.11% and a maximum energy-saving rate of 10.66% when the jet velocity is 2 m s −1 , the spacing distance is 13 mm, and the jet angle is 0°. Compared with a single non-smooth structure, the non-smooth jet coupling structure has a larger area of low shear stress regions and an increased thickness of the boundary layer bottom, which reduces the pressure drag and surface flow velocity.