6 Physical Model 



Model 



Design of model 



The Port Huron Harbor model (Figure 15) was constructed to an undistorted 

 linear scale of 1:60, model to prototype. Scale selection was based on the 

 following factors: 



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 repro- 

 duction 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 were as follows: 



Characteristic 



Dimension' 



Model-Prototype Scale 1 

 Relations | 



Length 



L 



U = 1:60 



Area 



L= 



A, = U^ = 1 :3,600 



Volume 



L' 



V, = U^ = 1:21 6,000 



Time 



T 



T, = L," =1 :7.75 



Velocity 



L/T 



V, = U* =1 :7.75 



Discharge 



LTr 



Q, = U='^= 1:27,871 



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



30 



Chapter 6 Physical Model 



