1.0 

 0.9 

 0.8 

 0.7 

 0.6 

 0.5 

 0.4|- 



_ "70/8 = 0.90 

 Tc/T = 0.25 





d/gT2 = 0.0008 

 H/gT2 =0.00031 



T/2 

 Time — 



Figure 2. Predicted monochromatic wave profile (after Dean, 1974). 



III. SOURCES OF DATA 



Sources of data upon which the predictive techniques are based include 

 laboratory data collected by the authors for a wide range of conditions, 

 laboratory data collected by other authors, and field data from the FRF at 

 Duck, North Carolina. Conditions under which these data were collected and 

 methods of analysis are described below. 



1. Laboratory Tests Conducted by Authors . 



a. Wave Conditions, Data, and Test Setups . Most of the monochromatic wave 

 data and all the irregular wave data collected over a horizontal bottom were 

 obtained in a 105.7-centimeter-wide channel within CERC's 1.2-meter-high by 

 4.5-meter-wide by 42.6-meter-long wave tank. The monochromatic wave data are 

 tabulated in Appendix A and the irregular wave data are tabulated in Appendixes 

 B and C. A gravel absorber beach with a slope 1 on 12 was used at the end of 

 the channel to reduce wave reflection to a low level. Four paralleled wire 

 resistance-type wave gages were used in the channel to record the wave condi- 

 tions. A plan view and a profile view of the test setup with gage locations 

 are shown in Figure 3. Figure 4 shows a short section of typical irregular 

 wave records taken approximately simultaneously at each of the four gages. 

 The time axis of the records has been shifted slightly to place the highest 

 crest in the center of each section to show the differences in the time 



