Improved coastal boundary condition for surface water waves

Surface water waves in coastal waters are commonly modeled using the mild s lope equation. One of thr parameters in the coastal boundary condition for this equation is the direction at which waves approach a coast. Three publi shed methods of estimating this direction are examined, and it is demonstra ted that the wave fields obtained using these estimates deviate significant ly from the corresponding analytic solution. A new method of estimating the direction of approaching waves is presented and it is shown that this meth od correctly reproduces the analytic solution. The ability of these methods to simulate waves in a rectangular harbor is examined. (C) 2000 Elsevier S cience Ltd. All rights reserved.