Hydrodynamic Research On Launch And Underwater Movement Of Navigation Body

The launch and underwater movement of navigation body are both important partsof the underwater launch section, their hydrodynamic forces and underwater trajectoryaffect the initial motion gesture of navigation body when it leaves the water surface, andthis is the ke y factor that determines the success of launch process. By studying thefactors that influence hydrodynamic forces and underwater trajectory of navigation body,the process of entire launch can be understood comprehensively, which is helpful toimprove the success rate of underwater launch. From the disciplinary po int of view, thisresearch project is an interdisciplinary which is related to fluid dynamics, flightmechanics and other disciplines. While from the content point of view, this research isalso related to some complex problem, such as the unsteady motion, the complexity ofmultiphase flow, turbulence and fluid-structure interaction.Firstly, a numerical simulation on the underwater movement of a navigation bodymod el was carried out through combining some advanced CFD technologies, such asmoving mesh and the UDF with FLUENT, a commercial computing software. Theresult of simulation shows that calculation result agrees well with experimental result,which verifies the correctness of the simulation result and method.Secondly，by using the abo ve-mentioned simulation method, a simulation wasconducted on navigation bodies with different tail structures and navigation bodieswhich have inflatable structure or not. The result shows that a tail structure with coverand sealing ring make the head of navigation bodies deflect more. At the same time, anavigation bod y with inflatable structure can help gas film form evenly on the surface.This gas film is also able to help reducing the surface resistance of navigation bod y andimpact load which is brought by bubble collapsing.At last, a simulation on navigation bodies, which were launched under differentconditions, was carried out. The result shows that the hydrodynamic force of navigationbody is more dependent on its initial deflection than other factors. Simultaneously,compared to small depth launch, large depth launch will increase the impact loadbrought by fluid and this will cause navigation body deflects more severely.