Line with floats: Properties of base line type

When modelling lines with floats, the line without floats is referred to as the base line type. It is assumed to be of circular cross section, and may be of either the homogeneous pipe or general line type category. We use the following notation for its properties.

\begin{align*} O\!D_l &= \text{outer diameter} \\ I\!D_l &= \text{inner diameter} \\ m_l &= \text{mass per unit length} \\ d_{\mathrm{n}l} &= \text{normal drag diameter} \\ d_{\mathrm{a}l} &= \text{axial drag diameter} \\ C_{\mathrm{Dn}l} &= \text{normal drag coefficient (for a homogeneous pipe)} \\ C_{\mathrm{Dx}l},C_{\mathrm{Dy}l} &= \text{$x$ and $y$ drag coefficients (for a general line type)} \\ C_{\mathrm{Da}l} &= \text{axial drag coefficient} \\ C_{\mathrm{an}l} &= \text{normal added mass coefficient (for a homogeneous pipe)} \\ C_{\mathrm{ax}l},C_{\mathrm{ay}l} &= \text{$x$ and $y$ added mass coefficients (for a general line type)} \\ C_{\mathrm{aa}l} &= \text{axial added mass coefficient} \\ \end{align*}

The normal added mass coefficients, $C_{\mathrm{an}l}$, $C_{\mathrm{ax}l}$, $C_{\mathrm{ay}l}$ are commonly taken as 1.0 for circular section; the axial added mass coefficient $C_{\mathrm{aa}l}$ is commonly taken to be zero.