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Green Water on Ship Decks
Marilena Greco
CeSOS, Centre of Excellence for Ships and Ocean Structures, Norway
Steps of Physical Investigation
Water shipping scenarios
Green-water kinematics and loads
Occurrence of impact phenomena
Occurrence of parametric roll
Research Tools: Model Tests
2D fixed structure 3D fixed ships
3D ships: heave & pitch 3D ships: parametric roll
Research Tools: Numerical Methods
Domain-Decomposition strategies
Potential Flow Solver:BEM
Navier-Stokes
Solver Coupling
Potential
Seakeeping
Solver
Shallow-water
approximation
PDB Water-on-Deck: Initial stages Initial area of the entrapped cavity
From experiments
Area/f2
m
f
max-f
= (max-f)/cf Kjeldsen & Myrhaug (1979)
The time of bubble fragmentation is well predicted
PDB Water-on-Deck: Initial stages
Experiments DD BEM-NS results
PDB Water-on-Deck: Initial stages
Air as ideal gas + adiabatic law in the cavity Incompressible cavity p=pa in the cavity
Experiments DD BEM-NS results
PDB Water-on-Deck: Initial stages Full scale versus model scale: cavity shape
From numerics (DD BEM-NS)
m
m
m
m
m
PDB Water-on-Deck: Later stages Water-front velocity
u/[g(max-f)m]0.5
x/ [(max-f)m]
u
x
From experiments
wf
PDB Water-on-Deck: Later stages Flow evolution and interaction with a superstructure
DD BEM-NS Air-water interface
PDB Water-on-Deck: Later stages Pressure on the wall: DD BEM-NS versus experiments
Experiments DD results
Experiments DD results
Water-on-Deck Problem Green-water loads: vertical superstructure
PDB HF
(p-p0)/(gD) (p-p0)/(gD)
From numerics (DD BEM-NS)
Water-on-Deck Scenarios Existence diagram
Dam-Breaking events
Plunging wave plus Dam-Breaking events
Hammer-Fist events
Plunging-Wave events
Marintek (2000)
White-Water events
3D Model Tests With Fixed Model Structure of the deck flow
Inner “blunt” structure
Dam-break like front
Transverse flow
Front bow motion
/ 1.25, 0.22, 0L kA Fr
3D Water on deck: Model Tests vs LSeak-NS DD
Experiments
3D DD
Side Bottom
Experiments
3D DD
/L=1.25, kA= 0.15, Fr= 0.189
waves
Exp.
Num.
Exp.
Num.
Exp.
Num.
Exp.
Num.
Deck Pressure: Model Tests vs WNLSeak-SW DD
wall
Probably due to with-spray jet impact before the main
water reaches the wall
Experiments: Parametric Roll & Water on Deck
FPSO free in heave, pitch and roll
in head sea waves
Front view
Side view
Parametric roll occurrence Numerical (WNLSeak-SW DD) transient phase
/L=1 kA=0.1
T and T4n in the signal T4n=2T in the signal
resonance & instability
T T4n
Front view Top view
Water-on-deck: Model Tests vs WNLSeak-SW DD
/L=0.75 kA=0.25: event after instability
Front view Top view
/L=0.75 kA=0.25: event after instability
Water-on-deck: Model Tests vs WNLSeak-SW DD
Front view Top view
/L=0.75 kA=0.25: event after instability
Water-on-deck: Model Tests vs WNLSeak-SW DD
Front view Top view
/L=0.75 kA=0.25: event after instability
Water-on-deck: Model Tests vs WNLSeak-SW DD
Front view Top view
/L=0.75 kA=0.25: event after instability
Water-on-deck: Model Tests vs WNLSeak-SW DD
Front view Top view
/L=0.75 kA=0.25: event after instability 0.5T4n=T
Water-on-deck: Model Tests vs WNLSeak-SW DD
1
2
3
4
5
6
7
Water-on-deck occurrence: Numerical Solution
Influence of parametric roll on the deck pressure
This research has been possible especially thanks to:
Dr. Claudio Lugni
CNR-INSEAN & CeSOS
Dr. Giuseppina Colicchio
CNR-INSEAN & CeSOS
Prof. Odd M. Faltinsen
NTNU & CeSOS
All 3D experiments were performed at CNR-INSEAN
Dr. Maurizio Landrini
CNR-INSEAN
Relevant References
Publications on Books •Faltinsen O.M., Greco M., 2011, Slamming and green-water phenomena on ships, in Marine Technology and Engineering:
CENTEC Anniversary Book. Editors: Soares C.G., Garbatov Y., Fonseca N., Texeira A.P., Technical University of Lisbon,
Portugal, Vol. 1.
Publications on International Journals •Colicchio G., Greco M., Lugni C., Faltinsen O.M., 2013, 3D Domain Decomposition for Violent Wave-Ship Interactions, Int. J.
for Numerical Methods in Engineering, accepted for publication.
•Greco M., Bouscasse B., Lugni C., 2012, 3D seakeeping analysis with water on deck and slamming. Part 2: Experiments and
physical investigations, J. of Fluids and Structures, 33.
•Greco M., Lugni C., 2012, 3D seakeeping analysis with water on deck and slamming. Part 1: Numerical solver, J. of Fluids and
Structures, 33.
•Colicchio G., Greco M., Faltinsen O.M., 2011, Domain-Decomposition Strategy for Marine Applications with Cavities
Entrapments, J. of Fluids and Structures, 27 (4).
•Colicchio G., Greco M., Lugni C., Faltinsen O.M., 2010, Towards a fully 3D domain-decomposition strategy for water-on-deck
phenomena, J. of Hydrodynamics, Ser. B, 22 (5).
•Greco M., Colicchio G., Faltinsen O.M., 2007, Shipping of Water on a Two-dimensional Structure: Part II, J. of Fluid
Mechanics, 581.
•Colicchio, G., Greco, M., Faltinsen, O.M., 2006, BEM-level set domain decomposition strategy for nonlinear and fragmented
interfacial flows, Int. Journal Numer. Meth. Engng, 67/10.
•Greco M., Faltinsen O.M., Landrini M., 2005, Shipping of Water on a Two-dimensional Structure, J. of Fluid Mechanics, 525.
•Greco M., Landrini M., Faltinsen O.M., 2004, Impact flows and loads on ship-deck structures, J. of Fluids and Structures, 19 /3.
•Faltinsen O.M., Landrini M., Greco M., 2004, Slamming in marine applications, J. Engng. Math., 48.
•Barcellona M., Landrini M., Greco M., Faltinsen O.M., 2003, An Experimental Investigation on Bow Water Shipping, J. Ship
Res., 47/4.