SOLUTION : 1? = Hg = 10 feet 



Using Equation 3-10 



or 



H = 1.416 H^, 

 s rms 



H .-1!^ = -15-. 7.06 ft 



'■'"^ 1.416 1.416 



(a) From Figure 3-5, curve b, it is seen that for P = 0.1 (10 percent) 

 ^^ « 1.80; Hjo = 1.80 H = 1.80(7.06) = 12.7 feet, say 13 feet. 



rms 



(b) Similarly, for P = 0.01 (1 percent) 



2.36; H^ = 2.36 H^^^ = 2.36 (7.06) = 16.7 ft., say 17 ft. 



"/ 



rtns 



Note that; 



^10 12.7 



H 10 ^<^ 



or H,„ = 1.27 H. 



and 



$ 



^ _ 1^ 

 H, ~ 10 



or H^ = 1.67 H^ 



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



Goodknight and Russell (1963) analyzed wave-gage observations taken 

 on an oil platform in the Gulf of Mexico during four hurricanes. They 

 found agreement adequate for engineering_application between such important 

 parameters as Hg, Hio, ihiax, ^rms^ and H, although they did not find 

 consistently good agreement between measured wave-height distributions 

 and the entire Rayleigh distribution. Borgman (1972) substantiates this 

 conclusion from wave observations from other hurricanes. These findings 

 are consistent with Figures 3-3, and 3-4, based on wave records recently 

 obtained by CERC from shore-based gages. The CERC data include waves from 

 both extratropical storms and hurricanes. 



3.23 ENERGY SPECTRA OF WAVES 



The significant wave analysis, although simple in concept, is diffi- 

 cult to do objectively, and does not provide all of the information needed 

 in engineering design. 



