AN IMPLEMENTATION OF THE METHOD OF AUXILIARY STATE VARIABLES FOR SOLVING SEAKEEPING PROBLEMS

Article type: Research Article

Authors: Sutulo, S. | Soares, C. Guedes

Affiliations: Unit of Marine Technology and Engineering, Technical University of Lisbon, Instituto Superior Técnico, Lisbon, Portugal

Abstract: An analysis of the problem of the conversion of frequency-domain model for linear seakeeping hydrodynamic forces into the corresponding time-domain representation is carried out. After a short consideration of the memory-functions method, the study is focused on the so-called Method of Auxiliary State Variables whose advantage is that the original mechanical system consisting of the ship and the surrounding fluid and having distributed parameters is approximated with a simpler lumped parameters system described by a relatively simple set of linear ordinary differential equations. An algorithm for determination of the coefficients of those equations based on the fractional approximation of the added masses and damping coefficients curves is proposed and tested.

Journal: International Shipbuilding Progress, vol. 52, no. 4, pp. 357-384, 2005