Conclusions 



236. Based on results obtained in this study, several important conclusions can be made about 2-D 

 small-scale movable-bed physical modeling of coastal scour. 



a. Mid-scale test results support preservation of the dimensionless fall speed parameter in an 

 undistorted Froude model as a viable method of scaling models intended to replicate wave 

 erosion under turbulence-dominated situations. The guidance has been verified for 2-D 

 Ccises, and must be further validated before it can be fully recommended for 3-D 

 movable-bed model tests. 



b. For tests involving regular waves, model designers should consider augmenting the 

 Froude-scaled experimental wave height to provide better prototype-to-model 

 correspondence of the Xie parameter in the offshore region. This correspondence should be 

 limited to the more active portions of the offshore and need not extend out to closure depth. 



c. Tests conducted using irregular waves do not require the augmentation described in (b) 

 above. 



d. Small perturbations in the fall speed parameter between prototype and model can be 

 tolerated without significant impact; however, this should be avoided if possible. 



e. Models in which temporal profile evolution results are important should begin with a 

 reasonable approximation of the natural beach profile molded into the model. Accuracy in 

 the offshore region is more important than surf zone detail. 



f. Comparable profile development can be achieved between regular and irregular wave models 



when the irregular significant wave height, Hij^, is equal to the regular wave height. Profile 

 development will take between two and three times as long in the irregular wave model. 



g. Dean's (1986) concept that the additional erosion experienced in front of a seawall is 

 approximately equal to the amount of sediment behind the seawall that would erode in the 

 seawall's absence seems to hold for the 2-D situation investigated in the wave flume. 



237. Further examination of these experimental results by others may reveal additional insights 

 overlooked by the authors or inconsistencies in the conclusions stated above. Such scrutiny is desirable and 

 encouraged by the authors in the spirit of scientific discovery. 



