Wave reflection from coastal structures is defined by the magnitude and phase of the reflected wave. Both properties have a profound impact on the wave kinematics and coastal processes in front of the structure. This paper focuses on the phase shift on reflection. Using a large experimental data set, involving normally incident and obliquely incident regular and irregular waves, it is shown that the phase is uniquely determined by a nondimensional number χ3 defined by structure slope, water depth at the structure toe, wave period, and angle of incidence. A theoretical method for predicting phase shift based on matching the equation for linear long waves on a sloping beach with an equation for flat-bed standing waves seaward of the structure toe yields good estimates of the phase shift at low values of χ3. A second method based on integration of the shallow water wave number over the slope is considered and not recommended. Example cases are presented that demonstrate the practical importance of the phase shift in determining the kinematics in front of the structure.
|Number of pages||9|
|Journal||Journal of Waterway, Port, Coastal and Ocean Engineering|
|Early online date||1 Mar 1998|
|Publication status||Published - 1 Mar 1998|