The wave heights in the movable-bed tanks varied from 0.31 to 0.45 foot 
(9.4 to 13.7 centimeters) in experiment 72B-06 and from 0.29 to 0.41 
foot (8.8 to 12.5 centimeters) in experiment 72B-10. Ignoring the first 
group of waves, the range of wave heights within the first 10 minutes was 
0.13 foot (4.0 centimeters) in experiment 72B-06 and 0.09 foot (2.7 centi- 
meters) in experiment 72B-10. In the fixed-bed tanks, again ignoring the 
first group, the range of wave height variation was 0.10 foot (3.0 centi- 
meters) in experiment 72B-06 and 0.07 foot (2.1 centimeters) in experiment 
72B-10. The range of wave height variation was lower in the fixed-bed 
tanks, as expected. 
The average wave height in each tank of each experiment was deter- 
mined by averaging the average of 10 waves in a 40-second interval during 
each minute. In the movable-bed tank, the average wave height was 0.41 
foot in experiment 72B-06 and 0.36 foot (11.0 centimeters) in experiment 
72B-10. Because the waves were recorded at the same distance from the 
profile and assuming that the initial reflectivity was the same, the 
difference in the average wave height was not due to reflection from the 
profile, but likely due to the difference in the initial test length, 
which affects the development of secondary waves and re-reflection from 
the wave generator. 
The average wave height in the fixed-bed tanks was 0.35 foot (10.7 
centimeters) in experiment 72B-06 and 0.30 foot (9.1 centimeters) in 
experiment 72B-10. In each experiment, the difference between the fixed- 
and movable-bed tanks was 0.06 foot (1.8 centimeters). This difference 
was probably due to the gage position at different points in the standing 
wave envelope, since the gages in the fixed-bed tanks were 7 feet farther 
from the profile than the gages in the movable-bed tanks (see Fig. A-1 in 
the App.). 
Table 5 presents the average incident wave heights in both fixed-bed 
tanks. These heights were determined by the automated method for deter- 
mining the reflection coefficient, Kp (see Vol. I). The range of vari- 
ation in the fixed-bed tank was 0.05 foot (1.5 centimeters) in experiment 
72B-06 and 0.04 foot (1.2 centimeters) in experiment 72B-10. This varia- 
tion was probably caused by generator operation variation, measurement 
errors, and errors not caused by a changing profile. 
The range of wave height variation in the movable-bed tank was 0.06 
foot in experiment 72B-06 and 0.03 foot (0.9 centimeter) in experiment 
72B-10. There was little significant difference in wave heights between 
fixed and movable bed of either experiment, indicating that the changing 
profile accounted for little of the variation. However, there was signif- 
icant difference in the average incident wave heights between the two 
experiments. This difference is likely due to the difference in initial 
test length, which was 38.3 feet (11.7 meters) longer in the 6-foot tank. 
b. Wave Reflection. The reflection coefficient, Kps data from 
experiments 72B-06 and 72B-10, as determined by the manual and automated 
methods, are given in Table 6. The two methods are described in Volume I. 
15 
