Simulation On Free Navigation Of Wave Glider Based On CFD Technique

With the strengthening of the exploration in ocean,scientists have designed a new kind of unmanned water surface vehicle called wave glider,which is driven by ocean wave energy,in order to operate a wide-range and long-term research on marine environment,and to expand the breadth and depth of exploration of the ocean.The wave glider has the ability to survive in ocean for a long period,operate a wide-range and comprehensive exploration of ocean environment.It has the advantages of strong vitality and low cost,which makes it has a broad application prospects.The wave glider,which consists of three parts:floating vehicle,submerged body(wave glider propulsor)and a flexible cable which connects other two parts,is a multi-body system incorporating with rigidity and flexibility.Ocean wave is the source of power for the navigation of wave glider.In order to truly reflect the propulsive performance and navigation process of the wave glider in ocean waves,it is necessary to analyze the hydrodynamic characteristics and to predict its velocity.However,as a multi-body system incorporating with rigidity and flexibility,the wave glider has a complex movement process which makes it hard to analyze its propulsive performance.Therefore,the author of this paper has carried out the simulation on the free navigation of wave glider in ocean wave and detailed works are listed as follows:Firstly,considering the structural feature of wave glider as a multi-body system incorporating with rigidity and flexibility,the author has established flexible multi-body dynamics model of the wave glider based on Flexible Structural Mechanics,realized six-freedom-degree motion by using overlapping grid technique and simulated the fluid environment based on SIMPLE Method,which laid the foundation for the simulation of the whole navigation processes of the floating vehicle and wave glider proplusor.Secondly,the author has simulated the generation and propagation of waves by using Volume of Fluid Method(VOF)and made a series of simulation on the free navigation process of wave glider in the state of primary sea,smooth sea,slight sea and moderate sea and analyzed its hydrodynamic characteristics and motion response under different sea state.Meanwhile,the author has changed the length of flexible cable and made simulations on the free navigation process of wave glider in different sea state and then analyzed the effects on its hydrodynamic characteristics and motion response caused by flexible cable whose length is changeable.Finally,free navigation tests of wave glider prototype were operated,one is lab experiment finished in the comprehensive test pool,and the other is marine experiment operated in ocean environment.The author has analyzed the movement of the prototype during the tests,and verified the accuracy of multi-body dynamics model of the wave glider and results of numerical simulation,which laid the foundation for the future application of the wave glider.