Practical Source Code for Ship Motions Time Domain Numerical Analysis and Its Mobile Device Application

Abstract

This thesis included developing MATLAB program source code for the six degrees of rigid body freedom time domain motions of a ship travelling with a specified mean velocity in waves. The code is developed to simulate canonical forced and free motions. This study followed the impulse-response function time domain method in which the hydrodynamic coefficients are computed using the 2-D linear strip method in the frequency domain and converted into the time domain. The equations of motion are then solved simultaneously. This study considers merchant ships except for ships with a buttock flow stern. Ikeda’s prediction is used for roll damping computation, and a good solution is achieved for vessels other than buttock flow stern ships in roll motion. A range of wave periods and speeds are also considered. Steady-state results are compared to other published results. The numerical method agrees with classical ship motions and published results. The present work explores ways to simulate ship motion in mobile devices. Two concepts are proposed: web-based simulation (WBS) and a stand-alone simulation. The latter approach is adopted. Two parts of the source codes are rewritten for the iOS platform: the motion related to memory forces and the calculation engine. The codes are tested in the iOS simulator, and the results are compared with the MATLAB solution. The world’s first mobile device application in naval architecture achieves a good simulation result.