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发表于 2011-12-28 15:40
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来自: 中国上海
应该是1/4船长(0.25L),从艏柱开始算起,甲板的空气管头和通风筒需要加强。
当然,其前提条件是船长要求大于80m,且空气管头位于的露天甲板距离夏季载重线的高度小于0.1L或22m(取小值),则需要加强。
加强的计算公式为:p = f ρ V2 Cd Cs Cp kN/m2 (tf/m2, Ltf/ft2)
where:
f = 0.5 (0.05, 0.0156)
ρ = density of sea water, 1.025 t/m3 (1.025 t/m3, 0.0286 Lt/ft3)
V = velocity of water over the fore deck, 13.5 m/sec (44.3 ft/sec)
Cd = shape coefficient
= 0.5 for pipes
= 1.3 for pipes or ventilator heads in general
= 0.8 for pipes or ventilator heads of cylindrical form with its axis in the
vertical direction
Cs = slamming coefficient, 3.2
Cp = protection coefficient:
= 0.7 for pipes and ventilator heads located immediately behind a
breakwater or forecastle
= 1.0 elsewhere including immediately behind a bulwark |
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