Study On The Navigating Characteristics Of High Speed Amphibious Vehicle Sailing In Head Sea

As a kind of special combat vehicles,Amphibious vehicle not only can travel on land,but also can pass through the rivers and lakes in the absence of other auxiliary equipment.Since its advent,it has experienced nearly a century of development.But in previous studies,The researchers put more emphasis on amphibious vehicle's performance in stable water.Especially their power performance in stable water.But the actual condition near the shore is more complex when amphibious vehicle is in the implementation of traveling and landing.According to statistics,there are different sizes of waves on the sea in about70% of the time.So it is very important to study the performance of the amphibious vehicle on the waves.this thesis uses CFD to simulate the motion of amphibious vehicle sailing in wave,the main research contents and results are as follows:First of all,this thesis based on linear small amplitude wave theory,adopting the simulation wave forms based on the approach of wave-generation method of defining inlet boundary conditions that can save numerical simulation computational resources and meet the accuracy requirements,using level set method to track the free surface,using the commercial CFD software CFX as a platform,realizes three dimensional numerical wave making.By changing the custom functions in the inlet boundary,more complex simulation of nonlinear waves can be realized.This made preparation for the next step-simulating the motion of amphibious vehicle in regular waves.Secondly,a numerical method basing on dynamic mesh for amphibious vehicle was established.By compared then chosen multiphase flow model and SST k-w turbulence model,established the numerical simulation method of amphibious vehicle navigate on the waves.Finally,Analysed the effects of various factors on the attitude,the force characteristics and the period of the amphibious vehicle by changing the speed,amplitude and wavelength.The flight attitude mainly involves trim and heave which are the most important two dgrees of freedom of navigating on the wave,force characteristics are mainly related to resistance,lift force and trimming moment.The results obtained from the study has some reference value to research and development of high performance amphibious vehicle.