Presented at SUC by Joe Zhang from DNV

1. SesamTM
Continuing 40 years success
Next generation HydroD and Recent development in HydroD
Fan Joe Zhang, Sesam BD Manager, Region Americas
December 03, 2012

2. Why HydroD 5?
Major architecture upgrade
Requested features for stability analysis
New requirements to reporting features
Part of overall plan to integrate modelling,
analysis and post-processing
Reduced memory usage
Request to utilize multiple CPU’s for UI
(responsiveness) and Stability
calculations
Request for Multiple views
Stronger script capabilities – full access to
model and results and integration with 3rd
part components (.NET)
SesamTM Continuing 40 years success
December 03, 2012
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3. New and improved features
Improved hydrostatic calculations
- More robust algorithms
- Inclusion of beams
New reporting functionality
- Stability reports
- Analysis documentation
SesamTM Continuing 40 years success
December 03, 2012
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4. User interface
Templates
Improved activity monitor
Add-ins
SesamTM Continuing 40 years success
December 03, 2012
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5. Changes in hydro models – concept models
Reuse of models in workspace
Compartment model separated from structural model
Use of FEM files
- Panel model
- Morison model
- Mass model
- Compartment model
- Structural model
SesamTM Continuing 40 years success
December 03, 2012
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6. New workspace
Template
Functions
SesamTM Continuing 40 years success
December 03, 2012
© Det Norske Veritas AS. All rights reserved.

7. Stability analysis example
SesamTM Continuing 40 years success
December 03, 2012
© Det Norske Veritas AS. All rights reserved.

8. Interactive definitions
SesamTM Continuing 40 years success
December 03, 2012
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9. More information, e.g. Structure model
Extra information
SesamTM Continuing 40 years success
December 03, 2012
© Det Norske Veritas AS. All rights reserved.

10. More information, e.g. loading condition
SesamTM Continuing 40 years success
December 03, 2012
© Det Norske Veritas AS. All rights reserved.

11. Stability analysis results
SesamTM Continuing 40 years success
December 03, 2012
© Det Norske Veritas AS. All rights reserved.

12. Recent development in HydroD/Wadam - Tank dynamics
Several isolated internal fluid domains with variable fluid density.
Could be full, or partially filled.
Change the total restoring matrix if internal free surface exist.
Added mass from the internal fluid.
SesamTM Continuing 40 years success
December 03, 2012
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13. Tank dynamics, Current approach and limitation 1
Tanks are identified from the structure model with dummy hydro pressure defined
for the panels enclosing each whole tank, with normal direction pointing from the
fluid towards the tank wall. LC numbering starting from 2, each LC correspond to
one tank. LC1 corresponds to the external wet hull.
The internal fluid is regarded as rigid body. No internal waves or relative motion.
Internal free surface is accounted (by HydroD) with additional restoring matrix.
Tank fluid Mass is calculated by HydroD and added to the total hull mass, to be
balanced with buoyancy force.
Filling fraction is defined in HydroD, the dummy hydro pressure property is removed
for the dry part of the panels if the tank is not filled.
User can control the location of the “Acceleration point” (ARP) and Zero level point
(ZRP)
SesamTM Continuing 40 years success
December 03, 2012
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14. Tank dynamics, the feature under development
The internal radiation is solved for each tank.
‫ ܣ‬൅ ‫ ܯ‬൅ ‫ݔ ݇݊ܽݐ_ܯ‬ሷ ൅ ‫ݔܤ‬ሶ ൅ ‫ ݔܥ‬ൌ ‫ ܨ‬
‫ ܣ‬൅ ‫ ܯ‬൅ ‫ݔ ݇݊ܽݐ_ܣ‬ሷ ൅ ሺ‫ ܤ‬൅ ‫݇݊ܽݐ_ܤ‬ሻ‫ݔ‬ሶ ൅ ‫ ݔܥ‬ൌ ‫ܨ‬
Load transfer
The zero pressure reference point will always be at the exact internal free surface.
The acceleration point is not needed anymore.
More accurate, no assumption.
SesamTM Continuing 40 years success
December 03, 2012
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15. Basic scenario
Internal fluid and external fluid is handled in exactly the same way
- Panel model and structural model need not be the same
- Panel model is automatically adjusted by Wadam to fit the free surface
- Same method for load transfer
SesamTM Continuing 40 years success
December 03, 2012
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16. Tank dynamics, New Approach
The dummy hydro pressure property need to be defined in Panel model to
distinguish the each tank panels and solve the internal radiation problem (in addition
to Structure model). Dummy hydro pressure with LC1 representing the external wet
hull -> LC2 … each for one tank.
Free surface cutting algorithm is applied to tank wet panels (the same as for
external wet hull, to secure the correct internal free surface level).
The balancing check updated. Now, mass model exclude the tank fluid.
Restoring correction is solved for each tank inside WADAM (not from HydroD
anymore), and added to the total restoring matrix.
Radiation problem solved for external hull and then loop through all tanks.
Load transfer and sectional load taking the radiation pressure and fluctuating
restoring pressure for each tank.
Full tank scenario.
SesamTM Continuing 40 years success
December 03, 2012
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17. Motivation for including internal fluid dynamics
More correct motions
- Include both added mass and restoring from the compartment
More consistent load transfer
- Same pressure loads in computation of motion and in load transfer
34838 2.1E6
New Old
SesamTM Continuing 40 years success
December 03, 2012
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18. Dynamic pressure
New Old
SesamTM Continuing 40 years success
December 03, 2012
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19. HydroD V4 modifications
Include dynamics of internal fluid
Checking include dynamics will disable Add mass and enforce Update stiffness
A parameter for internal fluid dynamics is written on Wadam1.FEM
- Global setting
Compartments are included in the panel model
HydroD5 – compartment model as a separate model
SesamTM Continuing 40 years success
December 03, 2012
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20. Safeguarding life, property
and the environment
www.dnv.com
SesamTM Continuing 40 years success
December 03, 2012
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