A Study of a Heaving Vertical Cylinder in a Towing Tank

Abstract

The effects of tank walls on experimentally measured hydrodynamic coefficients are of concern to researchers. In this numerical study of heaving vertical cylinders in a towing tank, the nonresonant, linear potential flow around a heaving cylinder in a towing tank has been formulated. The method used is based on a matching technique and on Graf's addition theorem. The calculations suggest that "blockage" or "wall effect" is more pronounced in shallow water tanks. A resonant frequency ω, corresponds to the frequency of a wave with a wave length equal to the width of the tank. For frequencies higher than ωr hydrodynamic coefficients are very close to infinite domain values for large values of the ratio of the tank beam to the cylinder radius. For frequencies less than ωr blockage correction to the hydrodynamic coefficients is necessary.