Simulations For The Water-exit Process Of Underwater Vehicles And Analyses On The Characteristics Of Loads

The process of water-exit is the key technology, which directly determines thelaunching result and the performance. Harsh wave environment adds the difficulty thatunderwater vehicles cross the phase boundary with the proper attitude angle andvelocity. However, physical experiments cost too much and there may be problems suchas the scale effect. Consequently, algorithms based on CFD techniques are potentialeffective complementary ways out for the research on similar projects.Assisted by the numerical wave tank that comprises the mathematical theories ofwave flow and wave-generation means, the motion model with multiple degrees offreedom was built with the application of dynamic mesh and other calculation methods.Water-exit movements under different levels and phases were simulated. According tothe output data, the traces of the center of gravity, velocities, attitude angles, angularspeeds, forces and moments were compared. Therefore how the factors aboveinfluences kinetic parameters and loads of the vehicle were analyzed.Based on the CFD outcomes, the pressure of the vehicle’s surface was extracted asthe input for finite element analyses with assumptions for the inner configuration,materials and constraints. The overall distribution of the stress and the strain wereobserved. Thus the safety of strength was checked.At last, referring to the research work and conclusions, practical suggestions werepresented for water-exit experiments of underwater vehicles.