(2) Description of the Programs . Two programs were used to process 

 the wave data. These programs and other programs discussed later are on 

 file in the Automatic Data Processing Office (CERDP) , CERC. The first pro- 

 gram, WVHTCN, edits the digitized wave crest and trough elevation data and 

 reduces any selected part of the data set. The program determines the 

 average wave height for the envelope and subtracts this average from each 

 individual wave to obtain the individual wave height deviation from the 

 mean. The running mean (averaged over an envelope wavelength) is calculated 

 at each point and subtracted from the individual wave height deviation 

 from the mean to obtain the individual wave height deviation from the local 

 mean. The local mean is then plotted superimposed on a plot of the local 

 mean versus distance. The wave height deviation from the local mean height 

 versus distance is also written on tape for input to the second program, 

 WVHTC2. 



WVHTC2 computes the best fit sine curve for the selected part of the 

 wave height deviation from the local mean curve. The values for the ampli- 

 tude of the sine curve, the standing wavelength, the phase angle at the 

 origin of the plot, and H/ivG (called ^/[yg) are written on the plot. The 

 steps in production are given in Appendix C. 



c. Comparison of the Two Methods . Results from the two methods of 

 data reduction are compared in Figures 14 to 17. Figures 14 and 15 (K^ 

 versus time for experiments 70X-06 and 70X-10) indicate that the time 

 variation in reflection is fairly well duplicated; Figures 16 and 17 (plots 

 of K^ for manual method versus automated method for the same two experi- 

 ments) show that the manual method gave higher values. An assumption in 

 using the wave envelope method for determining reflection coefficients is 

 that the heights of the reflected waves do not change significantly during 

 the several minutes required to record the wave envelope. 



VI. SURVEY DATA 



1. Data Collection. 



Profiles were surveyed using the coordinate system (Fig. 5). The 

 stations and corresponding elevations were recorded on sets of scanning 

 forms for each range, survey number, and tank (see App. A). 



a. Types of Surveys . Two surveys were made: regular and special 

 (more detailed) surveys. Regular surveys were taken after each run accord- 

 ing to the schedules in Table 2; special surveys were taken less frequently. 



(1) Regular Surveys . These surveys were taken along profiles at 

 ranges 2 feet (0.61 meter) apart--ranges 1, 3, and 5 in the 6-foot tank 

 and ranges 1, 3, 5, 7, and 9 in the 10-foot tank. Elevations were meas- 

 ured at 0.5-foot (0.15 meter) intervals from the back of the tank to 

 station +10, at 1-foot (0.30 meter) intervals from station +10 to +23, and 

 0.5-foot intervals from station +23 to the toe of the beach. An exception 

 was experiment 72D-06, where the section of 1-foot intervals was between 

 station +20 and +46. 



34 



