Two phenomena are affected by differences between the generator and 
the profile: re-reflection and secondary waves. The average incident 
wave height in the movable-bed tanks was 0.38 foot (11.6 centimeters) 
in experiment 72B-06 and 0.31 foot in experiment 72B-10; therefore, 
re-reflection differences may have caused some differences. Secondary 
waves were observed on the wave recordings. 
b. Tank Width. Tank width effects have been reported in Volumes 
II, III, V, and VI of the LEBS series. The overshadowing effects of 
the generator gap differences in this study precludes a separate analysis 
of tank width effects. However, the critical combination of tank width 
and wavelength caused the transverse wave condition. 
c. Generator Gap Effect. The transverse wave observed in experiment 
72B-10 was generated by the gap at the end of the generator blade and 
resulted in the following differences in profile shape between the two 
tanks. The wave heights over the profile in experiment 72B-10 were 
obviously confused as a result of the transverse wave. This may have 
caused the shoreline to become skewed, with range 9 landwardmost and 
range 1 seawardmost. The flat area near station 10 in the 10-foot tank 
was lower in elevation along range 1 than along range 9. The erosion and 
formation of the bars in the inshore zone of the 10-foot tank were unique 
and the erosion progressed from range 1 to 9 and the formation from 9 to 
1. Figure 43 compares the profiles along ranges 1, 5, and 9, and shows 
the lateral variations caused by the transverse wave. 
V. CONCLUSIONS AND RECOMMENDATIONS 
1. Conclusions. 
(a) In two experiments with a water depth of 2.33 feet, a wave 
period of 2.35 seconds, and a generator stroke of 0.24 foot (7.3 centi- 
meters) (generated-wave height of 0.34 foot), the average incident wave 
height was 0.38 foot in experiment 72B-06 and 0.31 foot in experiment 
72B-10 (Table 5). Reflection measurements in the control tanks with a 
fixed-bed profile varied from 0.03 to 0.06 in experiment 72B-06 and from 
0.02 to 0.09 in experiment 72B-10, indicating that the measurement error 
in determining Kp from the changing profile was +0.015 in experiment 
72B-06 and +0.035 in experiment 72B-10 (Table 6). 
(b) K, varied from 0.03 to 0.14 in experiment 72B-06 and the aver- 
age Kp in experiment 72B-10 varied from 0.11 to 0.24. The Kp in the 
10-foot tank varied considerably across the tank. Increases in Kp in 
experiment 72B-10 correlate well with changes in the upper part of the 
offshore slope. The Kp changes in experiment 72B-06 were not caused 
by any apparent change in profile shape (Fig. 43). 
(c) The profile in the 6-foot tank developed an equilibrium shape 
during the first 10 hours (Fig. 14). The profile in the wider tank was 
slowly, but continuously, changing, and never reached equilibrium (Fig. 18). 
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