THEORETICAL AND EXPERIMENTAL STUDIES OF 3-DIMENSIONAL WAVEMAKING IN NARROW TANKS, INCLUDING NONLINEAR PHENOMENA NEAR RESONANCE

In view of several practical ramifications of this problem, computatio nal-analytical techniques for calculating waves induced by heaving arb itrary bodies in narrow tanks have been developed, including nonlinear wave groups produced near tank resonance. These feature computational near-field solutions matched with appropriate far-field solutions. In the linear case, the far field is provided by linear mode superpositi on. In the nonlinear case, the far field is described by a suitable no nlinear evolution equation of the cubic Schrodinger type. Matching tec hniques were developed. Calculations were successfully carried out and the results 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 nonlin ear wave groups were obtained near resonance, and these are well repro duced in some detail by the nonlinear theory and computations, without considering any effects of dissipation. The related problem of resona nt wave groups produced by a segmented paddle wavemaker has also been treated by analysis and subject to computation, with good general agre ement with past experiments. The technique features matching near- and far-field computations using energy considerations.