Estimate of Breaking Wave Height Behind Structures

A useful and computationally simple method is given for estimating the wave breaker height and angle behind structures on a uniformly sloping bottom. The breaking wave height behind a structure is assumed to be proportional to the product of refraction, shoaling and diffraction coefficients with the incident wave height at the tip of the obstacle. The solution is obtained by iterating over breaking depth and starting angle at the tip of the structure, together with a breaking condition. The diffraction coefficient can correspond to either monochromatic or directionally random waves. A simplified procedure for calculating the diffraction coefficient of random directional waves is given in an appendix. The method has been verified with limited field and laboratory data. Possible refinements as well as limitations are discussed.