Using Equation 3-32 



T = 8.6 e 



RAp 

 200 



1 + 



0.104 a Vjp 



Vu7 



where the exponent 



RAP 36(2.31) 



200 



200 



= 0.416 



T = 8.6 e 

 s 



0.416 



1 + 



0.104 X 1 X 26 

 V91.6' 



Tj = 8.6 (1.52) (1.282) 



16.8 seconds. 



Alternately, by Equation 3-36, it is seen that 



T = 2.I3V59.4 = 16.4 seconds. 



It should be noted that computing the values of wave height and period 

 to three significant figures does not imply the degree of accuracy of the 

 method; it is done to reduce the computational error. 



Referring to Figure 3-34, H^ = 59.4 feet corresponds to the relative 

 significant wave height of 1.0 at r/R = 1.0, the point of maximum winds 

 located, for this example, 36 nautical miles to the right of the hurricane 

 center. At that point the wave height is about 60 feet, and the wave 

 period T is about 16 seconds. At r/R = 1.0 to the left of the hurricane 

 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 to that of the 59.4-foot wave . The significant wave period 

 for the 36.8-foot wave is: Tg = 2.13 /36.8' = 12.9 seconds, say 13 seconds. 



The most probable maximum wave is assumed to depend on the number of 

 waves considered applicable to the significant wave, H^ = 59.4 feet. This 

 number N depends on the length of the section of the hurricane for which 

 near steady state exists and the forward speed of the hurricane. It has 

 been found that maximum wave conditions occur over a distance equal to the 

 radius of maximum wind. The time it takes the radius of maximum wind to 

 pass a particular point is 



t = 



36 



26 



= 1.38 hours = 4,970 seconds; 



(3-37) 



the number of waves will be 



t 4970 



N = — = 



T, 16.4 



303. 



(3-38) 



3-61 



