(12.0 ft) and extend 5.5 m (18 ft) oft'shore ( or when scaled to 1:50, spacing of 

 183 m (600 ft), extending 275 m (900 ft) oft^shore. 



Based on Froude's model law (Stevens 1942) and the linear scale of 1:50, the 

 model-prototype relations in Table 1 were derived. Dimensions are in terms of 

 length (/) and time (/). 



Table 1 1 

 Model-Prototype Scale Relations at 1:50 Undistorted Scale J 



Characteristic 



Dimension 



1 

 Model-Prototype 

 Scale Relation 



Length 



/ 



/, = 1 :50 



Area 



P 



A, = 1,^ = ^ :2,500 



Volume 



P 



V, = l^= 1:125,000 



Time (tidal and short wave 

 period) 



t 



f^= ^ = 1:7.07 



Velocity 



l/t 



V = IJt, = 1:10 1 



Other scales may be assumed for the bathymetry, so the different scaling relation- 

 ships seen in Table 1 would apply. 



The Idealized Inlet Facility is connected to a large sump (volume of 1.98xl0*{ 

 (523,000 gal)) for water exchange so that tides may be produced in the facility's 

 ocean to drive tidal currents into and out of the inlet bay. A constant inflow is 

 introduced from the sump into the model ocean while a "rolling" gate either reduces 

 or increases flow area over an exit pipe into the sump, which causes ocean rise or 

 fell, respectively. The rolling gate is regulated by a controller connected to a 

 feedback loop comparing actual to desired water level. The two circular shapes in 

 Figure 1 are storage tanks each holding 182,(X)0 i (48,0(X) gal) water. They can be 

 used to simulate a much larger bay area by storing flood tide water and releasing it 

 back to the bay to flow to the ocean during ebb flow. Pumps and control valves 

 associated with this procedure are located adjacent to the storage tanks. 



A steady-state flow may also be established for ebbing or flooding currents. The 

 piping system is shown in Figure 1. Water is either collected (flood flow) or distri- 

 buted (ebb flow) through a system of manifolds in the bay which may be adjusted for 

 1, 2, or 3 bay channels or a uniform flow across the bay. Water is either released 

 (flood flow) or taken from (ebb flow) the ocean headbay to complete the circulation 

 which is energized by the pumps located in the upper left comer of Figure 1. 



Either irregular or monochromatic waves were produced by an 80-ft-long, 

 unidirectional plunge-type (vertical motion) wave generator (see Figure 1). 

 Unsealed wave periods could be varied from 0.5 to about 3 s and wave heights to 

 10 cm (at the generator location and for this particular arrangement of the 

 generator). Wave angle could be varied for specific tests by moving the generator 

 on its castors. 



Chapter 2 Experiment Arrangement 



