UFC 4-159-03
3 October 2005
Static Longitudinal Current Force for Ships. The longitudinal current
4-5.2
force is defined as that component of force parallel to the centerline of the vessel. This
force is determined for streamlined ship-shaped vessels from the following equation
(Naval Civil Engineering Laboratory (NCEL), TN-1634, STATMOOR A Single-Point
Mooring Static Analysis Program):
(15)
EQUATION:
where
Fxc =
total longitudinal current load (newtons)
FxFORM =
longitudinal current load due to
form drag (newtons)
FxFRICTION =
longitudinal current load due to skin friction (newtons)
FxPROP =
longitudinal current load due to propeller drag (newtons)
The three elements of the general longitudinal current load equation, FxFORM , FxFRICTION ,
and FxPROP are described below:
FxFORM =
longitudinal current load due to form drag
1
ρw Vc2 B T Cxcb cos(θc )
FxFORM =
EQUATION:
(16)
2
where
ρw
mass density of water, from Table 4-1
=
Vc = current speed (m/s)
B = maximum vessel width at the
waterline(m)
T = average vessel draft (m)
Cxcb = longitudinal current form drag coefficient = 0.1
θc = current angle (degrees)
FxFRICTION =
longitudinal current load due to skin friction
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