Numerical simulation and flow noise computation during transient launching process of torpedo in deep-sea simulator

Abstract

The transient launching process of a torpedo in a deep-sea simulator is a complex nonlinear fluid–solid coupling problem. Complex problems, such as projectile movement and gap flow, must be dealt with in the numerical computation. The launching channel is usually simplified to reduce computational cost, which affects the accuracy of the simulated flow field and acoustic computation results. The complete inner structure of the launching channel was retained in the numerical computations in this study to make the computation results much realistic. The spring mesh method and the radial basis function method were applied to update the mesh for the projectile movement, and a fine simulation was conducted on the launching flow field. The computation results related to torpedo movement were validated based on the test results, and the evolution of each flow structure in the deep-sea simulator was analysed. Based on the simulated flow field, acoustic computations were completed using the acoustic analogy method, and the acoustic characteristics, e.g. the propagation direction and sound source contribution of the launching noise, were analysed.