Hydrodynamic loads

We're working hard to write our manual, but aren't done with this section yet. This is a summary of the theory with the relevant references. 
Just drop us an email at feedback@simis.io if there's anything you're wondering about. 

The hydrodynamic loads are computed using the classical Morison equation (see Morison et al. (1950)). The force per meter applied on the nodes defining an element of the structure follows the equation

$$F_{hydro}(z) = \rho C_DR\mid u-\dot x \mid(u-\dot x) + \pi\rho R^2a + (C_M - 1)\pi\rho R^2(a - \ddot x)$$

$\rho$ is the water density [$kg \cdot m^{-3}$]

$C_D$ is the drag coefficient [-]

$C_M$ is the inertia coefficient [-]
$2R$ is the cross-sectional dimension of the element (diameter for a cylindrical cross section, width or length for a rectangular cross section) [m]

$u$ is the water particle velocity [$m \cdot s^{-1}$]

$a$ is the water particle acceleration [$m \cdot s^{-2}$]

$x$ is the displacement of the element [m] and a dot indicates differentiation with respect to time

$z$ is the vertical coordinate of the node [m]

Each load is then multiplied by half the length of the element and applied at the node. 
The water kinematics are computed using linear theory (also called Airy theory) for finite water depth. 

The following corrections can be applied: