A study on the performance of the cavitating flow structure and load characteristics of the vehicle launched underwater

This paper analyzes cavitating flow structure and load characteristics of vehicles launched underwater for different cavitation numbers and different angles of attack. The improved delayed detached-eddy simulation model and volume of fluid, as well as overlapping mesh technique, are adopted. Additionally, a verification of the underwater launch simulation method and cavitation model is presented. Cavitating flow structure, wall vortex structures, and load characteristics are studied with a focus on the evolution mechanism of the cavitation flow field during the water-exit process. The results show that the attached cavitation rapidly collapses from top to bottom under the combined effect of large-medium density difference and reentry jet. Due to the presence of attachment cavitation, the development of the wall vortex structure represented by the hairpin vortex is inhibited. Considering the compressibility of the vapor phase, the peak of the synchronous collapse pressure is much larger than the collapse pressure with incompressibility. The pressure appears to be characterized by short widths and high peaks during the collapse of the water-exit. As the vehicle exits the water with a certain angle of attack, the range and peak of the cavitation collapse pressure rapidly reduce. In particular, the pressure side cavitation shedding and collapse behavior at the initial moment may lead to a larger pressure peak.