B. Proposed Range of Experijnental Variables 



1. Wave length: 1 ft. to 2^ or 30 feet. 



2. Amplitude : to 1' . 



3. Period : 1 sec to 6 sec. 



U, Types of waves generated: Most of the waves will approach 

 the beach as Stokian or Cnoidal waves, since the flume size 

 limits the minimum practical value of X/y obtainable to 

 l/2. Deep water waves can be generated, but in an extreme- 

 ly limited range of wave lengths and depths. 



5. Beach slopes: Slopes corresponding to those most frequently 

 found on the shores of North America have been chosenj 



1 on 8 to 1 on 30. 



6. Roughness: Ssnd sizes have been selected to correspond with 

 the mean sand diameter found on the above range of North 

 American beaches. Range of mean sand diameter = 0.l5 mm to O.Uinm. 



7. Movable particles: It is planned to use spherical glass 

 beads supplied by the Beach Erosion Board, in Grades No. li 

 through 13 inclusive, corresponding to the roughness range 

 given in No. 6 above. 



C. Plan of Study 



1. Preliminary Study; on-shore, off-shore transport: 



a. Initially a beach of uniform slope covered with fixed 

 aand grains of uniform size will be used to produce a definable roughness, 



A section along the center of the slope will be covered with movable particles 

 of the same size as the fixed sand grains and a series of tests will be run 

 where each of the variables, depth, amplitude, wave length and slope will 

 be varied in turn. This will be done for both tjie smallest and largest 

 roughness and particles size listed above and will sei^re a three-fold 

 purpose: 



Clearer definition of the pertinent range of the variables. 



Provision of initial quantitative information as to the effect 

 of each wave characteristic on the motion of these two sizes. 

 This will provide an imderstanding of the mechanics of the 

 transport and a more intelligent approach to the problem of 

 selective sorting. 



Perfection of experimental procedure including calibration of 

 the wave machine. 



b. This part of the program may be extended to include the 

 complete range of particle sizes, a stabilized realistic beach profile 

 with sand ripples and internal velocity and turbulence studies if it ap- 

 pears advisable at the time. 



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