Research On The Mutiphase Flow In The Progress Of Vertical Water Entry Of Small Solid Of Revolution

The water entry progress of small supercavitating projectile has always been adifficult point and hot spot in the research of water entry. When the speed of theprojectile was high enough, the cavity formed around, generated by water vaporwhich is converted by the surrounding water since the pressure in surrounding flowfield drops below the saturated vapor pressure. The supercavitating projectile was anew weapon which could induce a cavity surrounding the whole projectile for asignificant reduction of drag. Compared with the general projectile，the cavitating ofwater，the compressibility of water and the consequent thermal effect must beconsidered because of super-high speed when modeling the water entry of smallsupercavitating projectile，which makes the domestic research work of this problemin a fledging period。The thesis first systematically reviewed and summarized the progress of waterentry research at home and abroad, especially the research on high and super-highspeed water entry. And then the mutiphase flow in the progress of vertical waterentry of small solid of revolution was researched by numerical simulation based onthe hydrodynamics analysis software FLUENT. The main works were as follows:(1)In the research on water entry at low speed, the general characteristic progress ofwater entry was analyzed, especially taking account of the influence of water entryvelocity and nose shape to the progress of water entry. The feasibility of numericalsimulation was validated by an experimental research result;(2)In the research onwater entry at high and super-high speed, the hydrodynamics analysis software wereimproved by embed the state equation of compressible water(i.e. Tait equation),andthe equation of sound speed in water to the numerical program, in order to realizethe simulation of the compressibility of water. Then the general characteristicprogress of water entry at high speed was analyzed, so as the influence of waterentry velocity and nose shape to the progress of water entry.The main innovations of this thesis were indicated in the following aspects:(1)the numerical simulation on the progress of vertical water entry were successfullyrealized by using the VOF multiphase model and six-degree of freedom dynamicmesh model, the computed result was certainly consistent with the experimentphenomena;(2) the Tait equation and the equation of sound speed in water wereembed to the FLUENT software by the user-defined function, which successfullyrealized the simulation of the compressibility of water，and a reasonable shock wave was simulated when the speed of solid of revolution was supersonic.