무한수심 부유체의 부가질량계수와 감쇠계수 결정을 위한 신 방법

A New Method for determining Added Mass and Damping Coefficients of Floating Objects in Infinite Water Depth: Residue Integration of Singular Free Surface Term

It has been the case that the added mass and damping coefficients of a floating body are determined differently depending on the water depth condition which is finite or infinite. In the present study, Green functions for the finite and infinite depth conditions are compared, and a new method based on residue integration technique is proposed to determine the singular integral of the free surface term in the Green function of infinite water depth. The new method is semi-analytic in that it does not depend on any approximate transcendental functions or numerical calculations as generally appeared in the existing methods. Hence, it can be more advantageous in both accuracy and calculation time. The method is numerically implemented to a floating hemisphere. The results are compared with those of existing numerical studies, and they showed nice agreements. The depth criterion to judge whether to use finite or infinite water depth is discussed as well.