Figure 2-27. Wave diffraction at Channel Islands Harbor breakwater, 

 California. 



If this last assumption is not valid then the processes of both refraction 

 and diffraction come into play. 



2. Diffraction Calculations . 



a. Waves Passing a Single Breakwater . From a presentation by Wiegel 

 (1962), diffraction diagrams have been prepared which, for a uniform depth 

 adjacent to an impervious structure, show lines of equal wave height reduc- 

 tion. These diagrams are shown in Figures 2-28 to 2-39; the graph coordinates 

 are in units of wavelength. Wave height reduction is given in terms of a dif- 

 fraction coefficient K' which is defined as the ratio of a wave height H 



2-77 



