PART V: REGULAR WAVE PERTURBATION TESTS 



Increased Wave Height 



134. The effect of a 10-percent increeise in wave height in the movable-bed physical model was 

 previously discussed in Part IV in conjunction with the observed improvement in the prototype-to-model 

 comparison for regular waves. This observation resulted in a suggested adjustment to the previously 

 presented scaling criteria when regular waves are used in the model. 



135. Representative model-to-model comparisons, where the only difference between the compared 

 tests was increased wave height, are shown on Figure 17 at equivalent stages of profile development. 

 Comparisons are plotted in model units and have not been scaled to prototype dimensions. In these plots, 

 the baseline case (profiles shown dashed) is test T03, and test T04 (profiles shown solid) is the case where 

 the monochromatic wave height was increased by 10 percent. Wave height statistics and profile listings are 

 given in Appendices B and C, respectively. Complete profile comparisons are presented in Figure E9 in 

 Appendix E. 



136. Increasing the wave height by 10 percent resulted in a 10-percent increase in wave steepness, 

 H/L, at the position of the nearshore wave gage. The 10-percent factor may have varied as the wave 

 underwent additional shoaling, but the wave steepness remained greater for test T04 up to the point of 

 wave breaking. The increased wave height in the physical model resulted in an increased offshore 

 movement of sediment due to the greater bottom water velocities under the steeper waves. A 

 corresponding adjustment in the nearshore region was also observed as sediment was transported seaward. 

 The larger regular wave heights also resulted in greater wave runup and more scouring of the berm after an 

 equivalent number of waves. It is not known if the observed difference in the surf zone after 1,650 waves 

 was due to the different sediment demand of the offshore bar or to the sediment deficit in the nearshore 

 region resulting from the presence of the revetment. 



Decreased Wave Period 



137. Test T07 was designed to be the same as the base test T03 except that the regular wave period 

 was decreased by 10 percent from the wave period used in test T03. This decreased wave period resulted in 

 shorter wavelength, which in turn increased the wave steepness, H/L, in test T07 over that of test T03. In 

 the shallow-water limit, where wavelength is proportional to wave period, a 10-percent decrease in wave 



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