Effect of roof impacts on coupling between wave response and sloshing

in tanks of LNG-carriers

B. Molin, F. Remy (Ecole Centrale Marseille)

A. Ledoux, N. Ruiz (Principia)

Experimental and numerical roll RAOsIrregular sea-state Tp=1.6s, Hs=0.034m.

Tanks 1 and 2: 19cm Tank 1: 39cm. Tank 2: 19cm.

ROOF AT FREE SURFACE. ADJUSTMENT OF ROLL VISCOUS COEFFICIENT

HS = 6 cm

ROLL RAO

ROOF AT FREE SURFACE. ADJUSTMENT OF ROLL VISCOUS COEFFICIENT

HS = 12 cm

ROLL RAO

FLAT ROOF 16 cm ABOVE FREE SURFACE. HS = 6 cm, TP = 1.6 s (NO IMPACTS)

ROLL RAO

FLAT ROOF 16 cm ABOVE FREE SURFACE. HS = 6 cm, TP = 1.6 s (NO IMPACTS)

RAO OF THE FIRST SLOSHING MODE

FLAT ROOF 16 cm ABOVE FREE SURFACE. HS = 6 cm, TP = 1.6 s (NO IMPACTS)

RAO OF THE THIRD SLOSHING MODE

FLAT ROOF 16 cm ABOVE FREE SURFACE. HS = 12 cm, TP = 1.6 s (A FEW IMPACTS)

ROLL RAO

FLAT ROOF 16 cm ABOVE FREE SURFACE. EXPERIMENTAL RAOS OF THE FIRST

SLOSHING MODE HS = 6, 9, 12 cm TP = 1.6 s

EXPERIMENTAL ROLL RAOSFLAT ROOF AT 16, 11, 5 cm.

HS = 12 cm TP = 1.6 s

HS = 6 cm

CHAMFERED ROOFS

MESH FOR DIOCUVE

EXPERIMENTAL ROLL RAOSFLAT VS. CHAMFERED 16 cm ABOVE F.S.

HS = 6 cm TP = 1.6 s

EXPERIMENTAL AND NUMERICAL ROLL RAOSFLAT VS. CHAMFERED 16 cm ABOVE F. S.

HS = 6 cm TP = 1.6 s

FLAT

EXPERIMENTAL AND NUMERICAL ROLL RAOSCHAMFERED ROOF 16 cm ABOVE F. S.

HS = 12 cm TP = 1.6 s

EXPERIMENTAL AND NUMERICAL ROLL RAOSCHAMFERED ROOF 11 cm ABOVE F. S.

HS = 6 cm TP = 1.6 s

EXPERIMENTAL AND NUMERICAL ROLL RAOSCHAMFERED ROOF 11 cm ABOVE F. S.

HS = 12 cm TP = 1.6 s

Conclusions

• Roof impacts do not seem to affect the roll response much

• Free surface non-linearities play a major role

• Chamfers effective by reducing free surface length

• Exploitation of test data still incomplete (roof impact loads)

FLAT ROOF 11 cm ABOVE FREE SURFACE