Numerical simulation on underwater vertical launching process under effect of initial gas

Abstract

The exiting-tube process is the basis and premise of the underwater vertical launching process. which is a multiphase, rapid, nonlinear, complex issue. Based on RANS method, combined the VOF multiphase flow model, high-resolution interface capture (HRIC) and overlapping grid (zero gap) technology, a complete mathematical model to describe the underwater exiting-tube process of the vehicle is established. The effects of the initial gas and launch parameters on the flow field and the load characteristics of the vehicle are systematically obtained. The research results indicated that: With the increase of the initial pressure of the initial gas, the force period of the vehicle increases, and the evolution process of the initial gas slows down. The initial gas pulsation period can be shortened by increasing the launch depth, while increasing the pressure at the shoulder of the vehicle and suppressing the natural cavitation of the vehicle. The increase of the lateral flow velocity will significantly increase the lateral force and deflection moment of the vehicle. The initial gas's pulsation process has a greater influence on the deflection moment and lateral force of the vehicle.

Keywords

• underwater vertical launching process
• numerical simulation
• multiphase flow
• initial gas
• overlapping grid