Comparison Between Numerical Computations and Experiments for Seakeeping on Ship Models With Forward Speed

Abstract

The recent progress of computers and numerical algorithms enables us today to use the translating and pulsating Green function in panel methods for seakeeping calculations. Two different methods of calculations of this function, its derivatives and their integrations over panels or segments, are briefly presented and have been introduced into the seakeeping codes Aquaplus developed at Ecole Centrale de Nantes and Poseidon at Laboratoire d'Etudes Aerodynamiques (LEA), Centre d'Etudes Aerodynamiques et Thermiques (CEAT). Both codes interchange the Fourier and boundary integrals on panels or waterline segments, the last part being performed analytically. These methods have been used to compute flows around Wigley or Series 60 model ships. To check the numerical results, an experimental setup has been developed at the CEAT that measures forces and moments on a model in forced harmonic oscillations of pitch or heave. Tests have been performed in the recirculating water channel of Ecole Centrale de Nantes on two L = 1.2 m Series 60 models of CB = 0.6 and 0.8 block coefficients. Unsteady wave patterns have been recorded using a resistive wave probe. The experimental results are compared with the numerical ones.