suc brasil 2012 : next generation hydrod and recent development in hydrod

Fan Joe Zhang, Sesam BD Manager, Region AmericasDecember 03, 2012

SesamTM

Continuing 40 years success

Next generation HydroD and Recent development in HydroD

© Det Norske Veritas AS. All rights reserved.

SesamTM Continuing 40 years success

December 03, 2012

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)

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December 03, 2012

New and improved features

� Improved hydrostatic calculations- More robust algorithms- Inclusion of beams

� New reporting functionality- Stability reports- Analysis documentation

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December 03, 2012

User interface

� Templates

� Improved activity monitor

� Add-ins

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December 03, 2012

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

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December 03, 2012

New workspace

Template

Functions



December 03, 2012

Stability analysis example



December 03, 2012

Interactive definitions



December 03, 2012

More information, e.g. Structure model

Extra information



December 03, 2012

More information, e.g. loading condition



December 03, 2012

Stability analysis results



December 03, 2012

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.

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December 03, 2012

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)

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December 03, 2012

Tank dynamics, the feature under development

� The internal radiation is solved for each tank. � �� _��

� � � � �_�� _��

� 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.

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December 03, 2012

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

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December 03, 2012

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 HydroDanymore), 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.

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December 03, 2012

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

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34838 2.1E6

New Old



December 03, 2012

Dynamic pressure

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New Old



December 03, 2012

HydroD V4 modifications

� 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

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Include dynamics of internal fluid



December 03, 2012

Safeguarding life, property and the environment

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suc brasil 2012 : next generation hydrod and recent development in hydrod

Technology

years successdecember

det norske veritas

tank panels

tank fluid mass

tank scenario

tank wall

toone tank

tank wet panels