UNIQUENESS AND TRAPPED MODES FOR SURFACE-PIERCING CYLINDERS IN OBLIQUE WAVES

Aspects of the solution to the linearized water-wave problem involving a pair of surface-piercing cylinders in oblique waves and infinite wa ter depth are examined. In particular, the solution is proved to be un ique for certain geometrical arrangements and wave parameters dependin g on whether the wave frequency is above or below the cut-off frequenc y. Outside these regions of uniqueness are constructed examples of non -uniqueness using ideas developed in McIver (1996) in the normal incid ence case. Although non-uniqueness examples are obtained numerically, we are able to prove the existence of non-uniqueness under the assumpt ion that the wave obliqueness is small.