Current Loads |
 
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Current Loads |
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Current loads in surge (FCy), sway (FCz) and yaw (MCθ) are calculated as follows:
(1)
where:
•CCy(αc), CCz(αc) and CCθ(αc) are the Current Coefficients in surge, sway and yaw respectively for an equivalent current incidence of αc
•ρw is the water density
•T is the body draft
•B is the body beam
•Lbp is the length between perpendiculars which is the sum of yfore and yaft
•yfore is the distance from the body centre of gravity to the forward perpendicular
•yaft is the distance from the body centre of gravity to the aft perpendicular
•uc is the equivalent current velocity
The equivalent current incidence αc is obtained using:
(2)
and the equivalent current velocity uc is given by:
(3)
where u' and ν' are the components, in the body axis system, of the relative body/current velocity.
u' and ν' are given by the equations:
(4)
where u and ν are the components in the body axes of the body CoG velocity, νc is the current velocity magnitude (which is a user input); and βc is the current direction as defined in Definition of Wind and Current Directions.
•*FLOATING BODY is used to define a floating body and its associated properties.Specifically, inputs such as draft, beam and length are used in the computation of current loads.
•*CURRENT is used to specify current loading.
•*CURRENT COEFF is used to specify current coefficients used to determine the current loading on a floating body.