Entering Table C-2 with d/L = 0.10, find tanh (27rd/L) = 0.5569.
From Equation 2-3 which is true for both first- and second-order
théories,
,
gL
i
(32.2) (200) (0.5569)
f
2
C2 = — tanh ---- = ------------------------ --- = 571 (tt/sec) ,
2n
\ L /
2tt
or
C = 23.9 ft/sec.
As a conséquence,
— = — = 0.0418 sec/ft .
L
C
Referring again to Table C-2, it is found that when
H
z = — ,
2
cosh
2n(z + d)
L
cosh [2tt(0.1 1)] = 1.249 ,
and when
H
z = — — ,
2
cosh
2n(z + d)
L
cosh [27r(0.09)] = 1.164 .
Thus, the value of u at
to first-order theory is
a crest and trough respectively according
4
1 249
UC>1 = - (32.2) (0.0418)
= 2.8 ft/sec ,
4
1 1 64
t,l = - (32.2)(0.0418) —— = - 2 6 ft/sec
2
1.2040
tt/sec .
2-44