Model for Decay of Random Waves in Surf Zone

Abstract

A model for the decay of random waves in the surf zone that requires transformation of only one representative wave height [root-mean square (RMS)] without making any assumption about the shape of the probability-density function is presented. The breaker decay model proposed by Dally is used as a starting point in the derivation of the new model. It is assumed that random wave properties in the surf zone may be obtained by individually transforming a large number of waves across shore and adding together the effect from each single-wave component. In deeper water, outside the surf zone, where wave breaking is negligible, a Rayleigh distribution is employed to characterize the randomness of the sea. This semianalytic model is compared with a complete Monte Carlo–simulation approach for different beach profile shapes, including barred profiles, and macrofeatures of wave height and energy flux transformation across the surf zone are similar for the two approaches. Comparisons are made in the paper with laboratory data from the SUPERTANK project and field data from the DELILAH project.