Study On Floodwater's Effects To The Roll Motion Response Of Broken Ships

The stability of a ship is the core problem . It has a large probability to tumble if the ship's hold is broken when it is sailing in the sea. So it is necessary to study the ship's damaged stability because the damage is unavoidable for every ship. Among all of the damage study, some people hammer at the study of the damage factor and the carrying capacity of the ship; Some people devote themselves to the study of the longitudinal strength of the ship after the damage. But there are scarcely ever study about the stability of the ship after the hold is broken, especially when the ship is sailing in the sea.It builds the equation of the intact and the damage ship's roll motion in this paper, and then solve the equation by using Matlab and analyse the calculation results simply. Then suppose the water in the damage hold will turn out to be wave in the cabin. Treat the moment result from the floodwater sloshing as the ship's dynamic roll moment. Then analys the affect to the roll equation by sloshing. This is the focal piont of this paper.The results of the hydrodynamic coefficients and wave force are achieved by empirical expressions. The dynamic roll moment is work out by FLOW-3D,one of the CFD softwares. And the volume of fluid (VOF) method is applied to track the routeof the free surface. Finally, the results of the ship's roll motion equation will be given by Matlab.Finally, this paper studies the roll motion of a fix-tugbo, it contrastive analysis the roll motion of the ship in regular beam sea and the results are given for both the intact and the damaged states. For the damaged status, the dynamic effect of the floodwater is studied , analysis the floodwate's dynamic effect when the water are in different damage locations. It is also analyse the floodwate's dynamic effect when the water is in different depth of the same damage basin. The results show that when the ship has large roll amplitude , the dynamic effect of the floodwater roll moment is large and is can not be neglected.