ssc-367 - Ship Structure Committee

‘P = 1.1671*TS .
For Y = 1, the fourth area moment is infinite. The crest period,
T~, is therefore zero.
For values of y other than one, the JONSWAP equation cannot be
mathematically integrated. The period relationships as a function
of Ycan be calculated by numerical integration of the wave spectrum
equation over the range from three-tenths of the peak frequency to
ten times the peak frequency.
The shape of the JONSWAP spectrum can be further adjusted by changing
the values of e. The e values are sometimes varied when the JONSWAP
spectrum is used to fit measured wave spectra.
.-
A.3.4
Scott and Scott-Wieqel Spectra
The Scott (Reference A.6) spectrum was also formulated to fit North
Atlantic weather data. The Scott spectrum is the Derbyshire
(Reference A.7) spectrum with S1ight modifications to the constants
in the equation. The spectrum equation is as follows.
s(w)
= 0.214*(Hs)2*exp[-(~-wm)/ {0.065*(U-Mm+0.26)}4]
for -0.26 < OJ-Wm < 1.65
= o, elsewhere.
where
A-15
2.3