10. Scale Relationships 



The test series was conducted on a reduced scale of roughly 1:15. 

 Representative profiles obtained during the study are shown in Figures 5 

 through 21; all dimensions are in actual model terms unless otherwise 

 specified. In Tables I through 8, both model and prototype terms are 

 listed where applicable. Prototype terms are computed according to Froude 

 relationships as follows: linear dimensions, such as length, height, width, 

 and depth are obtained by multiplying the actual model dimension by a factor 

 of 15: that is, I foot in the model is equivalent to 15 feet in the proto- 

 type. Volume dimensions, such as the amount of sediment moved by the device, 

 are computed by multiplying the actual model volume by a factor of 15^, or 

 3375; for example, 0.2 cubic feet in the model is equivalent to 675 cubic 

 feet in the prototype. Time dimensions are computed by multiplying the 

 actual time in the model by a factor of the square root of 15, 3.873, so 

 I hour of actual running time In the model is equivalent to 3.873 hours, 

 or 3 hours, 52 minutes in the prototype. In the discussion of the indivi- 

 dual test runs, prototype terms will be used throughout unless otherwise 

 specified. 



IV RESULTS 



I . General Description of Figures 6 through 21 



Figures 5 through 21 show the profiles that existed prior to and 

 after each run, and thus show the effect of the device. operation for each 

 run. For contrast, a 4X vertical exaggeration was employed. The tank wall 

 at the end of the tank opposite the generator is represented by the left 

 side of the graph. The solid line represents the profile that existed 

 prior to each run, and is so labeled; the dotted line shows the profile 

 as it existed after each run. The numbers along both the ordinate and 

 abscissa of each graph represent actual (not prototype) distances in the 

 model in feet. The Stillwater line is shown for each run and is so labeled. 

 The water depth, measured outside the flume near the wave generator, 

 labeled "offshore water depth", the wave period, and the wave height are 

 listed for each run in both model and prototype terms. The wave height 

 listed is the average of the wave heights recorded during each run as 

 measured by a dual-wire resistance probe located outside the mouth of 

 the flume in roughly the same depth as the offshore water depth. 



In each of the first seven runs (Figures 6 through 12) the location 

 of the wave gage between the device and the shore is marked and labeled. 

 Each position occupied by the device for any period of time is also marked 

 on each of the graphs showing the effects of device operation. It should 

 be noted that the dotted line (post-run) profiles do not always extend the 

 entire length of the solid line (pre-run) profile. By observing the device 

 in operation for short periods of time, it seemed that the area directly 

 affected extended only about 3 model feet on either side of the device. 

 This observation was severely limited by the shortage of window area in 



