Table 4. Prototype and Model Values of Xie's Parameter 



Prototype 

 Depth (m) 



{Umax - U, 



)/w 



Ratio of Xie's Parameter 



Proto. 



Base 



+ 10% 



f(C/„...-C/.)/»l6«.. 





5.0 



20.86 



18.15 



20.42 



1.15 



1.02 



4.5 



23.57 



20.84 



23.33 



1.13 



1.01 



4.0 



26.83 



24.09 



26.83 



1.11 



1.00 



3.5 



30.89 



28.09 



31.19 



1.10 



0.99 



3.0 



36.12 



33.33 



36.80 



1.08 



0.98 



2.5 



42.23 



39.42 



43.36 



1.07 



0.97 



2.0 



51.83 



48.97 



53.67 



1.06 



0.97 



117. It is also noted that this experimental result pertains to regular waves, whereas the natural 

 variability in wave height and period existing in irregular wave trains may help to compensate for the 

 differences in Xie's parameter without augmentation of the significant wave height in the model. This 

 possibility is investigated further in the section of this chapter discussing movable-bed model law 

 verification employing irregular waves. 



Experiment Repeatability 



118. As previously discussed, tests TOl and T02 were conducted with a smaller sand berm width than 

 was actually required. However, these tests were conducted in an identical manner to assess the 

 repeatability of the movable-bed model experiments. Figure 14 presents three profile comparisons between 

 model tests TOl and T02 plotted in model units. A complete set of comparisons is given in Figure E8 in 

 Appendix E (Repeatability Test)j and profile and wave data are given in the appropriate appendices. 

 Visual inspection of the profile comparisons indicates that the movable-bed model is very capable of 

 producing repeatable results. In fact, examination of the comparisons at the two sidewalls after 1,650 

 waves reveals that the observed cross-tank variation was also reproduced to a sufficient degree of accuracy. 

 Calculated RMS variations between the two experiments are given in Table 5. For reference, the values are 

 given in both model units (inches) and equivalent prototype units (metres) as determined using the 

 7.5 length scale employed in these experiments. 



48 



