Free-surface effects on the hydrodynamic coefficients of a laterally oscillating slender body at forward speed

Abstract

In order to predict the manoeuvring motion of a surface-piercing body in waves, one needs to know the hydrodynamic forces acting upon the body. The present paper describes a method to calculate these hydrodynamic forces on a laterally oscillating slender body at forward speed. The method is especially suited to take account of the free-surface effects, since the solution obtained satisfies the complete linearized free-surface conditions. Calculations are presented for various bodies at different speeds and frequencies, and the results generally indicate a clear improvement over ‘ordinary’ strip theory for cases where forward-speed effects are important.