PART II: THE MODEL 



Model Design 



4. Model tests were conducted in a wave tank 3 by 3 by 150 ft long. 

 This tank had a hydraulically actuated piston wave blade which was controlled 

 by an Automatic Data Aquisition Control System (ADACS) computer. In order to 

 reduce scale effects, the largest scale consistent with the available facili- 

 ties was used. The undistorted Froude scale used was 1:16 (model :prototype) . 

 Although this study was primarily concerned with overtopping rates for various 

 seawall/revetment configurations, armor stone size distributions for the model 

 revetments were carefully determined to correspond with prototype sizes de- 

 signed by NED in their planning studies (NED 1982). Based on Froude's Model 

 law (Stevens 1942) and the linear scale of 1:16, the following model-to- 

 prototype relations were derived (dimensions are in terms of length (L) and 

 time (T)): 



Characteri 



stic 



Dimension 



Model- to-Proto type 

 Scale Relations 



Length 





L 



L r = 1:16 



Area 





L 2 



A 2 , = 1:256 



Volume 





l3 



V r = l3 = 1:4,096 



Time 





T 



T = L 1/2 = 1 :4 



5. The specific weight of fresh water used in the model was assumed to 

 be 62.4 pcf and that of seawater 64.0 pcf. The specific weight of armor stone 

 used in the model and that proposed for the prototype was 165 pcf. These 

 variables are related using the following transference equation: 



( W a) (V) /L 

 v 'm _ v 'm [ _m 



(»a) = ('.)„ W 



(U " ' 



( S *) 



- 1 



m 



where 



W = weight of an individual armor stone, lb 

 m, p = model-to-prototype quantities, respectively 



