Skip to content

Home > Model Components > Lines > Winch Lines > Hydrodynamics

Winch Line Hydrodynamics

This sheet allows you to define the source for drag and added mass coefficients along the line. The drag and added mass data may be defined as follows :

  • Select "Use hydrodynamic data defined in the Segment types associated to the line": This assigns the drag and inertia coefficients which are defined within the Line Segment Types along the line (standard method).

    Note

    The standard method based on constant drag and inertia coefficients is used for most applications.

  • Select "Hydrodynamic data defined in the drag/lift database": This assigns an existing Drag/lift data property to the line. In this case, a selection box allowing you to choose the Drag/lift data property name from the available items is presented instead of the edit boxes and table for property values. Drag/lift data properties are listed in the Drag/Lift Database. This option allows you to define drag as a function of Reynolds number, water depth, position along the line, or fluid velocity heading relative to the cross section for non-circular sections (e.g. bundles and non-symmetrical cross-sections). This latter feature also allows the specification of lift and added mass coefficients, giving complete control over the hydrodynamic response of a line.

    Note

    The drag/lift data property must exist before you can choose this option. If none exist, a message appears giving you the option to create one now.

Note

The drag/lift data defined in this sheet sets the default drag/lift data that is associated with the line. The default Drag/lift data may be overwritten by any other existing Drag/lift data property by specifying so in the Calculation parameters. This allows conveniently running multiple analyses with the same line while changing the drag/lift data property.