142. Notice that the RMS variations calculated for the equal H/wT comparisons are in the same range 

 as those values obtained for experimental repeatability (Table 5), whereas in the two cases when there was 

 a 10-percent variation in fall speed parameters, the RMS variations are nearly twice are large. 



143. Clearly, the tests with equal values of H/wT exhibit good agreement and support the importance 

 of maintaining similar values of the fall speed parameter for this type of movable-bed modeling. However, 

 this correspondence was demonstrated only for small perturbations in the wave parameters used to express 

 the fall speed parameter. At some point, larger variations of the wave parameters to achieve similarity of 

 fall speed parameter will undoubtedly affect the hydrodynamics to the extent that satisfactory similitude of 

 profile evolution will not be achieved. As previously mentioned, tests T04 and TOT had similar values of 

 HI L, and it should be expected that similar profile response would be observed. 



Table 6. Wave Perturbation RMS Variations 



Model Dimensions (feet) 



Case 



80 Waves 



3T0 Waves 



1650 Waves 



Increased Wave Height 



0.15 



0.18 



0.14 



(T03 vs T04) 









Decreased Wave Period 



0.16 



0.13 



0.18 



(T03 vs T07) 









Equal H/wT Parameters 



0.05 



0.11 



0.09 



(T04 vs TOT) 









Prototype 



Dimensions (meters) 





Case 



80 Waves 



3T0 Waves 



1650 Waves 



Increased Wave Height 



0.35 



0.40 



0.33 



(T03 vs T04) 









Decreased Wave Period 



0.36 



0.30 



0.41 



(T03 vs TOT) 









Equal H/wT Parameters 



0.12 



0.26 



0.21 



(T04 vs TOT) 









144. The Froude criterion for scaling hydrodynamics is apparently still the best approach; however, the 

 results (Table 6) suggest that the experimenter may have some latitude in applying the Froude scaling 

 guidance and still achieve reasonable modeling results. 



61 



