Published online by Cambridge University Press: 21 April 2006
A mathematical model is constructed to represent the diffraction of plane harmonic waves through a gap between two semi-infinite breakwaters in water of constant depth. The boundary-value problem corresponding to this model is formulated and then specialized to the case of waves that are long relative to the gap width. A solution to the long-wave problem is found using the method of matched asymptotic expansions. A selection of results are presented and, where possible, comparisons are made with previous work.