A finite difference wave refraction-diffraction model

A refraction and diffraction model for the propagation of linear harmonic water waves is described in this study. It is followed the approach presented by Southgate ( 1989 ). The nearshore wave field is evaluated using a propagation method, and so initial and lateral boundary conditions must be given. The system equations are approximated by the finite difference technique. Two numerical schemes of the model equations are compared: (I) explicit and (II) implicit. The lateral boundaries are simulated using the radiation condition, or assuming a non-variable wave field in the x-direction, or assuming Snell's law to be valid along them. Model results are compared with data from the experimental circular shoal test of Ito and Tanimoto (1972 ). Results show that the model can be applied to simulate wave refraction and diffraction phenomenas in large coastal areas.