OrcaFlex User Group 2003 www.orcina.com Slide 1 of 10

OrcaFlex - Variable Data

Presentation Outline

• So what is Variable Data in OrcaFlex?

• Which data are variable?

• Hydrodynamic Variable Data

• Load Variable Data

• Externally calculated data

• Structural Variable Data

OrcaFlex User Group 2003 www.orcina.com Slide 2 of 10

OrcaFlex - Variable Data

What is Variable Data?

• Previously, most user defined data was treated as a constant throughout the simulation

• Now, certain data can vary during the analysis - in a pre-determined manner

• These can be as a function of simulation time, or of another variable

• External Functions: Allow interface with user defined external software

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OrcaFlex - Variable Data

Which Data are Variable?

OrcaFlex User Group 2003 www.orcina.com Slide 4 of 10

OrcaFlex - Variable Data

Hydrodynamic Variable Data(1/2)

• Current Direction = F(Simulation time)

• Current Speed = F(Simulation time)

What do these allow me to model?

• Loop currents (change both speed and direction)

• Tidal cycles

• Pre-determined shielding of current

• Horizontal Variation Factor = F(Distance)

OrcaFlex User Group 2003 www.orcina.com Slide 5 of 10

OrcaFlex - Variable Data

Hydrodynamic Variable Data(2/2)

• Drag Coefficient = F(Reynolds No., Re = V.D / )

• Fluid Temperature = F(Water Depth)

• Kinematic Viscosity () = F(Temperature)

• Normal Drag as a function of Re

What do these allow me to model?

OrcaFlex User Group 2003 www.orcina.com Slide 6 of 10

OrcaFlex - Variable Data

Load Variable Data

• Load Force = F(Simulation time)

• Load Moment = F(Simulation time)

• Tension = F(Simulation time)

What do these allow me to model?• Time varying forces & moments on Vessels and 6D

Buoys (use OrcaFlex as a ‘Simulator’)

• Sophisticted winch tension sequences

OrcaFlex User Group 2003 www.orcina.com Slide 7 of 10

OrcaFlex - Variable Data

Structural Variable Data(1/2)

• Axial Stiffness: % Strain vs. Tension

• Bending Connection Stiffness: BM vs. Angle

• Bend Stiffness: Bend Moment vs. Curvature

What do these allow me to model?• Non-linear axial stiffness (for man-made ropes)

• Non-linear Bend Stiffness (esp Bend Limiters)

• Non-linear con. stiffness (Bend Stiffeners)

OrcaFlex User Group 2003 www.orcina.com Slide 8 of 10

OrcaFlex - Variable Data

Structural Variable Data(2/2)

• Expansion Factor = F(Simulation time)

• Payout Rate = F(Simulation time)

• Wing Orientation = F(Simulation time)

What do these allow me to model?• Line thermal expansion effects

• More winch control sophistication

• Control how much lift is generated for ‘birds’

OrcaFlex User Group 2003 www.orcina.com Slide 9 of 10

OrcaFlex - Variable Data

Externally Calculated Data

• User defined external functions

What do these allow me to model?

• User defined software called repeatedly

• Re-calculates value of Variable Data item

• Passes this back for OrcaFlex to use

OrcaFlex User Group 2003 www.orcina.com Slide 10 of 10

OrcaFlex - Variable Data

Conclusion

• General purpose ‘Variable Data’ code architecture

• Powerful functionality for modelling non-constant data

• Extended control over operational sequences