Added mass of a circular cylinder under a free surface

Abstract

When a circular cylinder is immersed in a fluid of infinite extent and oscillated in such a manner that drag effects are negligible, it is well known that the closed form solution gives an added mass coefficient of 1.0. However, when boundaries are placed in proximity to the cylinder, and the cylinder oscillated parallel to the boundary, the added mass varies from the classical result. The forces acting on the cylinder in the latter case are dependent upon the proximity of the boundaries as well as the frequency of oscillation. It was the purpose of this study to experimentally determine the total force on such a cylinder in proximity to an impermeable bottom surface and under a free surface and to relate this force to the added mass coefficient. Experimental data was reduced using a computer program and the results presented graphically as a function of dimensionless parameters.