Drag Reduction Design And Hydrodynamic Performance Optimization Of Flanks On Amphibious Vehicles

Amphibious vehicles have been widely used in many fields,such as military,industry,agriculture,rescue,transportation,marine development,and so on.Most of the existing amphibious vehicles are in the drainage stage of low-speed navigation,and the water rapidity is difficult to meet the amphibious mission requirements of modern landing war.Three ways to improve water rapidity are to improve propulsion efficiency,reduce water resistance and improve engine power.The research shows that the drag reduction design can obtain the best fast performance.The research object of this paper: the amphibious unmanned platform adopts the walking mechanism of a four-stage crawler.When the vehicle is sailing in the water,the crawler is located on the impact surface of the first wave,the water filling phenomenon of the wheels is serious,and the stress concentration is significant,which greatly increases the navigation resistance and impact stress of the vehicle.In view of the defects and shortcomings of the existing drag reduction schemes,focusing on the influence of the walking mechanism of the amphibious unmanned platform on the water resistance,this paper puts forward the flank drag reduction design scheme and carries out in-depth analysis and research.The results of this paper can provide an effective solution for the amphibious unmanned platform to improve the water rapidity.The main research work includes:(1)This paper puts forward the flank drag reduction scheme,designs the flank layout scheme,expounds the flank drag reduction mechanism,designs the flank retraction mechanism,establishes the flank numerical simulation calculation model,and analyzes the influence of flank on hydrodynamic performance.The flank can not only reduce the total navigation resistance of amphibious vehicles but also optimize the trim and heave of the vehicle in the water,so as to help the vehicle move quickly with a better body attitude.The flank numerical simulation results correspond to the analysis conclusion of the flank drag reduction mechanism.(2)The Flanks configuration will affect the hydrodynamic performance of amphibious vehicles.This paper expounds on the influence mechanism of Flanks configuration,puts forward the Flanks configuration optimization scheme,and verifies the optimization effect of the configuration scheme.Hydrofoil drag reduction is not only a single function of hydrofoil dynamic lift,but also closely related to vehicle trim angle and navigation attitude.(3)In this paper,the real ship model towing test is carried out,and the towing test data and CFD simulation results are compared and analyzed.The resistance and trim curves are in good agreement,which verifies the correctness of the Flanks numerical simulation calculation method.The self-propelled test platform is designed and built,and multiple groups of self-propelled tests are carried out at different speeds to verify the drag reduction effect of the Flanks at high speed.This paper analyzes and optimizes the Flanks of the amphibious unmanned platform from three levels: theory,simulation,and experiment.The Flanks drag reduction scheme,the hydrodynamic research method of the complex flow field around amphibious vehicles,the Flanks configuration optimization scheme,and the effectiveness verification method of Flanks drag reduction proposed in this paper all provide new ideas for the drag reduction design of amphibious vehicles and lay a certain research foundation for improving the water rapidity of amphibious vehicles.