Bionic Drag Reduction Of Flexible Surfaces Based On Bi-directional Fluid Solid Coupling

With the development of science and technology,the concept of sustainable low carbon environmental protection has been deeply rooted in the hearts of the people.The problem of drag reduction is of great significance for the energy consumption of mechanical transportation tools.The energy consumption of vehicles,including cars,aircraft and ships,is mainly derived from friction resistance.When the ship is sailing,the friction resistance can reach 70% of the total resistance.When the car is driving,the friction resistance of the flow field outside the body of the body can reach to 80% of the total resistance.The friction resistance is mainly produced by turbulence.Considering the distinguishing feature of the flexible surface with drag reduction and noise reduction,this paper selects the polyurethane elastomer as a flexible material,and mainly studies the drag reduction effect of the flexible polyurethane elastomer surface in the turbulent state.This paper takes the porpoise skin as a biological prototype,and extracts the structural features of the dermis ridge of the dolphin epidermis to study the drag reduction effect of flexible polyurethane elastomers under turbulent conditions at different velocities.Taking Workbench as the background and using the turbulence model of Transition SST,the simulation of bi-directional fluid solid coupling analysis of flexible polyurethane elastomer plate is carried out first.Through numerical simulation,the results are as follows: compared with the rigid plate,the flexible polyurethane elastomer plate has a drag reduction effect in the flow velocity of 3~20 m/s,and the drag reduction rate can reach more than 10% when the velocity is higher than 10 m/s;As the velocity increases,the larger deformation section of polyurethane elastomer moves along the flow direction.So the friction resistance of the flexible polyurethane elastomer is reduced.Then,the simulation results of low velocity rate are verified by the cyclic tank experiment with differential pressure resistance method.The experimental results are basically consistent with the numerical simulation results.Finally,this paper combines the drag reduction characteristics of the flexible surface and non-smooth groove surface,simulates it in the same way,analyzes the drag reduction effect of the high speed flow field,and compares it with the drag reduction effect of the rigid plate.The results show that the flexible non-smooth groove surface also has the effect of drag reduction when the velocity is 10m/s,but the effect of drag reduction is less than that of flexible smooth.The numerical simulation results also provide some reference value for intelligent reduction of flexible coupling.