hence 



L = 



50 



= 270 feet 



0.1854 

 Evaluation of the constant terms in Equations 2-13 through 2-16 gives 



HgT 

 2L 



gTTH 



cosh (27rd/L) 



1 

 cosh (27rd/L) 



18 (32.2) (8) 

 2(270) (1.758) 



18 (32.2) (tt) 



(270) (1.758) 



4.88, 



= 3.84. 



Substitution into Equation 2-13 gives 



u = 4.88 cosh 

 From Table C-1 find 



27:(50- 15) 



270 



[cos 60°] = 4.88 [cosh (0.8145)] (0.500). 



lird 



= 0.8145 , 



and by interpolation 



and 



Therefore 



u = 

 w = 



"x = 



a = 



z 



cosh (0.8145) = 1.3503, 

 sinh (0.8145) = 0.9074. 



4.88 (1.3503) (0.500) = 3.29 ft/sec , 

 4.88 (0.9074) (0.866) = 3.83 ft/sec , 

 3.84 (1.3503) (0.866) - 4.49 ft/sec^ 

 -3.84 (0.9074) (0.500) = - 1.74 ft/sec^, 



Figure 2-3, a sketch of the local fluid motion, indicates that the 

 fluid under the crest moves in the direction of wave propagation and 

 returns during passage of the trough. Linear theory does not predict any 

 mass transport; hence the sketch shows only an oscillatory fluid motion. 



************************************* 



2.235 Water Particle Displacements . Another important aspect of linear 

 wave mechanics deals with the displacements of individual water particles 

 within the wave. Water particles generally move in elliptical paths in 

 shallow or transitional water and in circular paths in deep water. If the 



2-15 



