Experimental study of waves breaking over coral reef topography of a composite slope

A series of wave-flume tests were performed to study the characteristics of regular waves breaking on coral reefs, including the breaker type, breaker height, breaker position and surf-zone width. The tests were performed on the composite slope section of a reef rim at the specified conditions combined with serial wave heights and wave periods for two water levels. The test studied the criteria for differentiating the breaker types, assessed the applicability of the four breaker indexes on coral reefs with a composite slope, and provided an experience formula describing the breaker position and surf-zone width. Thus the following conclusions were drawn:the breaker types could be differentiated by the ratio of reef-edge water depth to the deep-water wave height; in the relational expressions of four breaker indexes, the correlation between the ratio of breaker height to deep-water wave height and the deep-water wave steepness was the best; the deep-water wave height and reef-edge water depth had great influence on breaker position and surf-zone width; with the increase in the ratio of deep-water wave height to reef-edge water depth, the dimensionless breaker position (the ratio of distance between the breaker point and the reef edge to the reef-edge shallow-water wave length) decreased and the dimensionless surf-zone width (the ratio of surf-zone width to reef-edge shallow-water wave length) increased.