HYDRODYNAMIC INTERACTION BETWEEN 2 VERTICAL CYLINDERS IN WATER-WAVES

The hydrodynamic interaction between two vertical cylinders in water w aves is investigated based on the linearized potential flow theory. On e of the two cylinders is fixed at the bottom while the other is artic ulated at the bottom and oscillates with small amplitudes in the direc tion of the incident wave. Both the diffracted wave and the radiation wave are studied in the present paper. A simple analytical expression for the velocity potential on the surface of each cylinder is obtained by means of Graf's addition theorem. The wave-excited forces and mome nts on the cylinders, the added masses and the radiation damping coeff icients of the oscillating cylinder are all expressed explicitly in se ries form. The coefficients of the series are determined by solving al gebraic equations. Several numerical examples are given to illustrate the effects of various parameters, such as the separation distance, th e relative size of the cylinders, and the incident angle, on the first -order and steady second-order forces, the added masses and radiation- damping coefficients as well as the response of the oscillating cylind er.