On Study Of The Hydrodynamic Interactions Between Two Underwater Moving Bodies

A mathematical model, computational method and some experimental results are presented for the hydrodynamic interacting forces and moments between two 3-D bodies moving in an unbounded water domain. This work is stimulated by a study of the hydrodynamic interactions when a UUV approaching to a parent submarine.Based on the potential flow theory and the general dynamics principle, two kinds of formula for calculating hydrodynamic forces and moments, which are in Lagrangian form and Bernoulli form, and a lot of corresponding numerical results using Bernoulli formula are given. During body surface grid discretization, the plane surface at body stern and the bow-stern asymmetry factors are given special attentions. There also provide some validity checks to Fortran90 programs and grid discretization modes in the thesis.Flows over a 2-D Rankine oval or a 3-D Rankine ovoid near a plane wall have been computed and the present numerical results agree well with that of viscous calculations as a whole concept. Some differences in value may be due to the omission of the fluid viscosity. The hydrodynamic interactions between two approaching or disparting spheroids, between two parallel torpedo-type or airplane-type platforms, between fore-and-afterward symmetrical UUV or platform and parent submarine have been investigated numerically, from which some interaction laws are drew.A preliminary model experiment has also been conducted on the near-wall-interference of torpedo-type platform at different inflow speed. The test results agree with the computational results in general. The discrepancy is believed to be due to the complexity in real fluid domain and needs farther research.The present method is applicable to any number of arbitrary shaped bodies in arbitrary motion in an unbounded fluid domain.