A time domain simulation method for nonlinear motion and wave loads of fast ships

Article type: Research Article

Authors: Shan, Ma | Wenyang, Duan

Affiliations: Multihull Ship Technology, Key Laboratory of Fundamental Science for National Defence, College of Shipbuilding Engineering, Harbin Engineering University, Harbin, China

Note: [] Corresponding author: Duan Wenyang, College of Shipbuilding Engineering, Harbin Engineering University, No 145-41 Nantong Street Nangang District, Harbin 150001, China. Tel./Fax: +86 451 8256 9123; E-mail: [email protected].

Abstract: A nonlinear time domain method is presented to calculate the vertical responses of fast ships. The extended 2.5D theory is used to evaluate nonlinear fluid radiation and diffraction forces which can take into account both the effects of the change of the underwater wet surface and the forward speed of a fast ship at free surface. A matched boundary integration equations algorithm is applied to solve the 2.5D theory in order to avoid numerical divergence observed when ships have large flare. The hydrostatic and Froude–Krylov forces are calculated below the incident wave elevation. The comparison of numerical results with model test data shows that the numerical method can capture the main nonlinear effects and is valid for the calculation of vertical motions and wave loads of high speed ships.

Keywords: Nonlinear wave induced loads, high speed vessels, 2.5D theory, numerical divergence, matched boundary integration equations

DOI: 10.3233/ISP-2009-0055

Journal: International Shipbuilding Progress, vol. 56, no. 1-2, pp. 59-93, 2009