VI-151 



Another kind of model 1s one In which a specific machine Is 

 developed and constructed which will reproduce certain of the 

 natural phenomena In the laboratory. These normally are 

 flumes, wave basins, or some other single-phenomenon simulating 

 device. 



Utilizing these laboratory simulation devices, the following 

 studies should be conducted. 



(a) Large movable flume tests using the typical 

 range of littoral drift material (sand and shell) 

 found along the coast are essential to verify or 

 modify the various sediment transoort formulas; 

 determine lower and upper limits for apolication of 

 such formulas; Improve definition of roughness 

 coefficient with changing geometry, sand riffles, and 

 dunes; and determine definite usable values of 

 entrainment functions and tractive force (bottom 

 shear stress) . 



(b) Utilizing three dimensional wave basins, studies 

 should be done to help yield first approximation 

 designs of inlet and inlet model studies to help 

 locate and determine the size and shaoe of .ietties; 

 determine effects of winds and waves on tidal flov/, 

 erosion, siltation, sediment transport, and sand by- 

 oassino; and check the effects of density currents 



