This method is simplified by assuming that the vessel is in head seas. The sectional Froude-Krilov and diffraction forces are obtained which makes this method suitable for the loads calculations.
The head seas approximation to the sectional Froude-Krilov wave force is given in Equation ( 31 ), note that this equation includes the water density, r, and the wave amplitude, z. This follows the work of Salvesen et al. (1970), Equations STF-32, 33
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Expanding the sine and cosine terms, this may be rewritten as follows:
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( 32 ) |
where:
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b |
is the total section beam. |
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d |
is the section draught. |
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As |
is the section area. |
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is the section area coefficient.
Note that |
Secondly, the head seas approximation to the sectional diffraction wave force is given in Equation ( 33 ), note that this equation includes the water density, r, and the wave amplitude, z:
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Expanding the sine and cosine terms, this may be rewritten as follows:
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( 34 ) |
where:
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a33 |
is the section added mass in heave. |
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b33 |
is the section damping in heave. |
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