PART II: THE MODEL 



Model-Prototype Scale Relationships 



5. Tests were conducted at a geometrically undistorted scale of 1:57.5, 

 model to prototype. Scale selection was determined by the following condi- 

 tions: (a) absolute size of model breakwater sections necessary to ensure the 

 preclusion of stability scale effects (Hudson 1975), (b) capabilities of an 

 available wave generator, and (c) the depth of water at the toe of the break- 

 water. Based on Froude's model law (Stevens et al. 1942) and the linear scale 

 of 1:57.5, the following model-prototype relations were derived. Dimensions 

 are in terms of length (L) and time (T), 



Model-Prototype 



Characterist 



ic 



Dimension 

 L 



Scale Relation 



Length 



L^ = 1:57.5 



Area 





l2 



A^ = lJ = 1:3,306 



Volume 





l3 



V = L^ = 1:190,109 

 r r 



Time 





T 



T = v}''^ = 1:7.58 

 r r 



6. The specific weight of water used in the model was assumed to be 

 62.4 pcf and that of seawater to be 64.0 pcf; specific weights of model break- 

 water construction materials were not identical with their prototype counter- 

 parts. The variables are related using the following transference equation: 



("4 ^A 



N. 



n 



- 1 



£ 



where 



W = weight of an individual armor unit, lb 



subscripts m and p = model and prototype quantities, respectively 



Y = specific weight of an individual armor unit, pcf 



Lj^/Lp = linear scale of model 



S = specific gravity of an individual armor unit 



relative to water in which the breakwater is con- 

 structed (i.e., S = Y /y , where y is the 

 ' a a w ' w 



specific weight of water, pcf) 



