WAVEMAKING BY HEAVING BODIES IN LONG TANKS, INCLUDING NONLINEAR GROUP FORMATION NEAR RESONANCE

In view of several practical ramifications of this problem, computational-analytical techniques for calculating waves induced by heaving arbitrary bodies in narrow tanks have been developed. These feature computational nearfield solutions matched with appropriate far field solutions. In the linear case, the far field is provided by linear mode superposition. In the non-linear case, the far field is described by a suitable non-linear evolution equation of the cubic Shrodinger type. Matching techniques were developed. The results of calculations confirm the important effect of tank walls on added mass and damping. Results of computations have been compared with some data obtained with a conical wavemaker in a narrow tank. Pronounced wave groups were obtained near resonance, and these are very well reproduced in considerable detail by the non-linear theory and computations, without considering any effects of dissipation.