Session: 06-12-02 Ship Hydromechanics II

Paper Number: 79532

79532 - A Contrastive Study of Two-Time Scaled Method and Unified Method in Maneuverability-in-Waves 

Maneuverability in waves, which is associated with navigation safety and overall operational efficiency, attracts more and more attention from worldwide scholars recently. There are two widely used theoretical methods on this topic, the two-time-scale method, and the unified method. However, both methods have theoretical limitations. For the two-time-scale method, it is based on the assumption that the maneuvering frequency varies a lot from the seakeeping frequency. Actually, this assumption is not achieved when the ship navigates in following wave conditions. Mine while, this method is also based on one hypothesis that the total ship motions can be considered as the linear superposition of the maneuvering motion and the seakeeping one. For the unified method, the wave forces rely on the interpolation of the precalculated force coefficients or semi-empirical results in general. Therefore, the comparison between the predicted results using these methods and the experimental results is necessary and emergent to assess the error and advantages of these methods. In the present study, two in-house codes using these methods are developed and utilized to predict the motions of S175 containership in regular waves. The results are obtained and compared with the experimental ones. Finally, the conclusions and assessments on these methods are obtained.

Presenting Author: Chengqian Ma Shanghai Jiao Tong University

Authors:

Chengqian Ma Shanghai Jiao Tong University
Ning Ma Shanghai Jiao Tong University
Xiechong Gu Shanghai Jiao Tong University