The random number seed value for the random phase generation was 

 different for the two depths. These two signals were scaled to achieve three wave 

 heights for each water depth by adjusting the gain on the output amplifiers for the wave 

 board command signal as indicated in Table 4.2. The resulting six time series of the 

 command signals sent to the wave board are shown in Figure A. 1 in Appendix A. Note 

 that short segments at the beginning and end of each series have been cut off in the 

 analysis. The spectra for these six signals are shown in Figures A.2 and A.3, for the two 

 water depths. The wave board was commanded at a rate of 20 Hz, and ramps of 5 sec 

 each were placed at the beginning and end of the command time series to gradually start 

 and stop the wave generator. 



4.3.2 Wave measurement 



Waves were measured using capacitance-type wave gages. Two arrays of 

 three gages, offshore and nearshore, were used as shown in Figure 4. 1. Nearshore gage 

 layout is shown in Figure 4.5. Considering the largest wave measured herein, this gage 

 location approximately corresponds to the reconmiendation by Goda (1985) where the 

 design breaking wave is determined 5H, seaward of the toe. This is the travel distance 

 of large breaking waves. For the toe depth o{h,= 1 1.9 cm, the depth at the most 

 nearshore gage was 16.5 cm, and the depth at the offshore array was 1 12.7 cm. For h, = 

 15.8 cm, the depth at the most nearshore gage was 20.4 cm and the depth at the offshore 

 array was 116.5 cm. 



64 



