Free and Forced Cross-Shore Long Waves
Low frequency motion in and outside the surf zone generated by grouping in the incident short waves is considered in a two-dimensional model. This groupiness has two primary effects, which are shown to be of the same order of magnitude. One is the long forced wave bound to the incident short waves, and the other is a time-varying position of the break point, which also contributes to the forcing of low frequency motion (or long waves).
Free, long waves are formed where the short-wave forcing undergoes changes due to shoaling or breaking or by reflection of bound waves. Mathematically this is a consequence of imposed boundary and matching conditions.
The presence of the induced long waves significantly changes the bottom velocities in a way that suggests a close connection with the formation of longshore sand bars.
KeywordsBreak Point Short Wave Forced Wave Surf Zone Radiation Stress
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