Multiphase coupling dynamics and evolution characteristics of the muzzle flow field in underwater asynchronous launches

This study explores the multiphase coupling characteristics and evolutionary mechanisms of the flow field in an underwater asynchronous launching. By integrating computational fluid dynamics simulation, high-speed imaging techniques, and experimental validations, the research elucidates the evolutionary characteristics of the muzzle multiphase flow field under asynchronous launching conditions. The volume of fluid method is employed to trace and computationally address the multiphase interfaces, while the realizable k-epsilon turbulence model is utilized to solve the gas-liquid turbulence mixing effects in the flow field. Based on this foundation, a three-dimensional unsteady multiphase flow model is used to analyze the complex interactions among the water, gas, and solid phases of the muzzle multiphase flow field of a dual-barrel underwater gun at varying launch time intervals. The results indicate that the interaction between the gas jet and water generates vortices on both sides of the muzzle, with shorter firing intervals leading to earlier muzzle vortex formation in dual-barrel asynchronous launches. The Mach disk structure in flow field I (created by the first projectile) forms approximately at 0.15 ms, while flow field II (created by the subsequent projectile), being disturbed by flow field I, forms the Mach disk later (at 0.2 ms). Moreover, a shorter firing time interval is associated with a further delay in the formation of the Mach disk in flow field II. The axial displacement of the Mach disk in both flow fields exhibits exponential growth over time.