SOLUTION ; Calculate, 



d 4.5 



= 0.0046 



2 2 

 gT 9.8(10) 



H 3.0 



= 0.0031 



2 2 

 gT 9.8(10) 



From Figure 7-68, 



L4 = 0.41 L^ = (0.41) (|^) T^ = 63.9 m (209.7 ft) 



From Figure 7-69 , 



n^ = 0.85 H = 2.6 m (8.5 ft) 



From Figure 7-70, 



L = 1.165 L4 = 1.165 (63.9) = 74.4 m (244.1 ft) 



and from Figure 7-68, 



K = '/ (^ = -^> = 0.9 



H (z = 0) 



^2 ^ % (z = -d) ^ ^^3^ 

 ^D (z = 0) 



Note the large increase in n^ above the Airy estimate of H/2=1.5m(4.9 



ft) and the relatively small change of drag and inertia forces along the 



pile. The wave condition approaches that of a long wave or shallow-water 

 wave. 



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



*************** EXAMPLE PROBLEM 18************** 



GIVEN ; Same wave conditions as preceding problem: H = 3.0 m (9.8 ft) and 

 T = 10 s ; however, the depth d = 30.0 m (98.4 ft) . 



FIND ; Crest elevation above Stillwater level, wavelength, and the relative 

 variation of force components along the pile. 



7-109 



