ssc-367 - Ship Structure Committee

Applied Wind
Speed Vz(t)
ft/s (m/s)
Mean Wind
Speed Vmz
ft/s (m/s)
.---------_
Cyclic Wind Probability
Speed vz(t) of
ft/s (m/s) Occurrence %
4.26 (13)
78.7 (24)
101.7 (31)
134.5 (41)
154.0 (50)
180.4 (55)
29.5 (9)
62.3 (19)
78.7 (24)
101.7 (31)
124.6 (38)
131.2 (40)
13.1 (4) 16.7
16.4 (5) 45.8
23.0 (7) 12.5
32.8 (10) 16.7
39.4 (12) 4.2
49.2 (15) 4.2
Table A-2 Applied, Mean
Extreme Gust Environment
and Cyclic Wind Speed Distribution for an
A.9.3
Gust Spectra
The power spectral density function provides information on the
energy content of fluctuating wind flow at each frequency
component. A study of 90 strong winds over terrains of different
roughness in the United States, Canada, Great Britain, and Australia
at heights ranging from 25 feet (8m) to 500 feet (150m) allowed
Davenport (Reference A.12) to propose a power density spectrum of
along-wind gust (the longitudinal component of gust velocity).
A modified version of the Davenport spectrum, due to Harris
(Reference ??), is given by:
m=qf
kV;
(2 + f’)$i’
where:
A-26