Applied Loading |
 
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Applied Loading |
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Hydrodynamic loading on the floating platform includes the various items listed below. The loads are computed for the floating body as a whole, and then applied at an appropriate location in the global force vector (e.g. at a node which corresponds to a centralised location such as the centre of gravity).
•First-Order Wave Loads (high frequency) derived from Force RAOs
•Wave Radiation Loads. An important issue arises with respect to the Added Mass and Radiation Damping terms associated with the floating body, and how these are modelled in the time domain. The frequency-dependent nature of these terms is accounted for using the established impulse response approach developed by Cummins (1962), and its implementation in Flexcom is described in detail by Connaire et al. (2003) and Lang et al. (2005). Specifically, the frequency-dependent damping term is replaced by a convolution integral of retardation functions and velocity time histories in the time domain.
•Viscous Damping Loads. These may be derived from centralised Viscous Damping Coefficients at some point on the floating body, or simulated in a distributed manner via Morison's Equation.
•Second-Order Wave Drift Loads (low frequency) derived from Quadratic Transfer Functions (QTFs)
•Current Loads computed via Current Coefficients
•Wind Loads computed via Wind Coefficients
•Hydrodynamic Loads determined according to the theory of manoeuvrability
•Diffraction-Radiation Theory & Morison's Equation discusses the main differences between these hydrodynamic modelling approaches.
•Floating Body Modelling Detail discusses relatively simple (concentrated loads) and more complex approaches (distributed loads) for physically modelling the floating structure.