Numerical Investigation On Cavitation Water-Exit Process Of Submarine Vehical

Submarine vehicle technology has been took more and more attention by various countries in recent decades. Cavities would be formed near the head and end wall of the vehicle during underwater motion. The impact of bubble collapse in the process of passing through the water would increase a dynamic load to the vehicle and influence vehicle motion. Consequently, researches on exit-water cavity become significant.This paper based on the ANSYS_FLUENT 12.0 software. Numerical simulations of cavitation tunnel test on some common axisymmetric headforms under different civitation numbers was made by using the Mixture multiphase flow model and the Zwart-Gerber-Belamri cavitation model in order to validate the correctness of that cavitation model by comparing simulation data with experimental data.Based on the basic research, Numerical simulation of cavitation water-exit process about different speed and different depth was carried out. The exiting motion was achieved by dynamic mesh method and UDF was used to write out the pressure change files of monitoring points. The water-exit process was divided to three periods which are underwater period, shoulder exiting period and tail exiting period. Analysis on pressure, velocity, streamlines, phase of the flow field and the develop or collapse process of cavitation in each period was carried out to compare differences between cavitation and uncavitation background, and analysis the influences of different speed and different depth.Wave simulation and verification about different wave levels was made based on the wave creating principle to make sure the rationality and accuracy of the wave making method. Base on that numerical simulation about the exiting process under different wave level and different wave phase was carried out, analysis on the simulation results was made to compare and investigate the influences of cavitation, wave level and wave phase.The results showed that in the cavitation water exiting process, the wall of the submarine vehicle would bear high pressure because of the collapse of shoulder cavity or tail cavity, which made the forces effect on the vehicle wall more complex. Large motion velocity would bring evidence cavitation which made both the value and the change rate of the wall load increase. Large water depth would make the shoulder cavity full developed, but has less effect on the tail cavity. Water death could change the distribution of the load on the wall but make less effect on the value of the load.The existence of wave made cavity difference between the anti-water side and back-water side, which could become more evidence during the exiting process. Wave can bring an effect similar to peeling off the high pressure area which made the high pressure away from the vehicle wall and reduced the load on the wall. Large wave level could bring stronger influence and increase the possibility of the peeling effect. The phase of wave could take effect on the relative size of cavity on the two sides, the length and thickness on the back-wave side would be obviously larger while wave crest phase, and the wave trough phase is just the opposite. Wave phase could make a small effect on the distribution of load on the vehicle wall during the shoulder exiting period, but almost had no effect to the tail.