Orcina papers & technical notes

Details of the non-linear hysteretic soil model in OrcaFlex, including comparisons against measured results, and investigations of its effects on an example steel catenary riser.

Description of the implementation of wake interference modelling in OrcaFlex. This paper was presented at the ISOPE conference in July 2008.

Details of the bending hysteresis modelling facilities in OrcaFlex. This paper was presented at the OMAE conference in June 2007.

This document describes the link between mesh refinement and results quality in a diffraction analysis. We demonstrate how symmetry conditions, calculation method and meshing technique can be used when trying to report converged results.

This document contains a list of some of the modelling issues that can lead to statics convergence failure. It explains how to recognise and avoid these issues.

This document explains the different methods available to model contact in OrcaFlex, and gives examples of typical uses of each.

This document explains an issue that can arise when modelling near-surface spar buoys.

This document describes the equation of motion that OrcaFlex builds and solves for the spar buoy object. This note supplements the OrcaFlex documentation.

This document, along with 'OrcaFlex Friction Effects', discusses the application of Coulomb friction from a physical and mathematical perspective. These notes supplement the OrcaFlex documentation.

This document, along with 'Friction Effects and Shear Stiffness', discusses the application of Coulomb friction from a physical and mathematical perspective. These notes supplement the OrcaFlex documentation.

This document discusses dynamic compression in catenary lines and associated high frequency curvature response. The note explains how to determine whether the response is physical or numerical, and offers suggestions on how to reduce possible over-conservatism in the model or load case matrix.

This document explains the benefits of discretising Buoys in OrcaFlex

Guidance on how to use a spar buoy connected to a vessel to model a buoy, so that frequency-dependent added mass & damping (and other vessel facilities, such as 2nd order wave load if wanted) can be used.

This document outlines how strain is reported in OrcaFlex.

This document explains how the old line target damping on the general data form in OrcaFlex (now on the numerical damping page of that form) relates to the effective % critical damping as normally understood by engineers.

This document describes: (1) the units used in OrcaFlex for linear seabed stiffness, and how these relate to the more common units of force per unit penetration per unit length of line. (2) a way of setting a reasonable value for seabed stiffness.

This document summarises how OrcaFlex can be used in support of the analysis methodology outlined in BV guidance note NI 604 DT R00 E (Fatigue of Top Chain of Mooring Lines due to In-plane and Out-of-plane Bendings).

This document gives details of the formulae used for random wave spectra in OrcaFlex.

This document discusses how to generate Spectral RAOs and why you might use them.