Using Equation 3-32
RAp
8.6 e200
0.104 a VF
R
where the exponent
RAP
200
36 (2.31)
200
= 0.416
T. = 8.6 e0-416
0.104 X 1 X 26
1 + ------ j
X
V91.6
s
= 8.6 (1.52) (1.282) = 16.8 seconds.
Altemately, by Equation 3-36, it is seen that
s
16.4 seconds.
the values of wave
It should be noted that computing
to three significant figures does not imply the degree of
method; it is done to reduce the computational error.
height and period
accuracy of the
to the relative
maximum winds
of the hurricane
Referring to Figure 3-34,
= 59.4 feet correspon s
significant wave height of 1.0 at r/R = 1.0, the poin °
located, for this example, 36 nautical miles to the ng
center. At that point the wave height is about 60 ee , an
hurricane
period T is about 16 seconds. At r/R = 1.0 to the e
about
center, from Figure 3-34 the ratio of relative significant height is about
0.62, whence H„ = 0.62 (59.4) = 36.8 feet. This wave is moving in a direc
tion opposite ?o that of the 59.4-foot wave. The significant wave period
for the 36.8-foot wave is: Ts » 2.13 /36Jf = 12.9 seconds, say 13 seconds.
The most probable maximum wave is assumed to dépend on the number of
waves considered applicable to the significant wave,
= 59.4 feet. This
number N dépends on the length of the section of the hurricane for which
exists and the forward speed of the hurricane. It has
conditions occur over a distance equal to the
time it takes the radius of maximum wind to
near steady State
been found that maximum
radius of maximum wind.
pass a particular point
wave
The
is
R
t
'F
a z
— =1.38 hours = 4,970 seconds;
26
(3-37)
the number of waves will be
t
N = -
. 303.
16.4
(3-38)
3-61