2 The Model 



Design of Model 



The Noyo River and Harbor model (Figure 3) was constructed to an un- 

 distorted linear scale of 1 :75, model to prototype. Scale selection was 

 based on such factors as: 



a. Depth of water required in the model to prevent excessive bottom 

 friction. 



b. Absolute size of model waves. 



c. Available shelter dimensions and area required for model construction. 



d. Efficiency of model operation. 



e. Available wave-generating and wave-measuring equipment. 



/. Model construction costs. 



A geometrically undistorted model was necessary to ensure accurate re- 

 production of wave and current patterns. Following selection of the linear 

 scale, the model was designed and operated in accordance with Froude's 

 model law (Stevens et al. 1942). The scale relations used for design and 

 operation of the model are shown in the following tabulation: 



Characteristic 



Dimension 1 



Model-Prototype Scale Relations 



Length 



L 



Lf = 1 :75 



Area (A) 



L 2 



A r = L 2 = 1 :5,625 



Volume 



L 3 



■V- r = L 3 = 1 :421 ,875 



Time 



T 



T r = L? 72 = 1:8.66 



Velocity 



L/T 



V r = L? /2 = 1:8.66 



Roughness (Manning's coefficient n) 



.1/6 



n r = L r 1/6 = 1:2.054 



Discharge (Q) 



L 3 /T 



Q r = lf /Z = 1:48,714 



1 Dimensions are in terms of length (L) and time (T). 





Chapter 2 The Model 



