Estudo da influência do nível de alagamento sobre a estabilidade dinâmica de pesqueiros.

Abstract

RODRIGUES FILHO, ODILON. On the influence of the level of flooding in the dynamic capsizing of ships. 2006. 126p – Dissertation (Master) – Escola Politecnica, Universidade de Sao Paulo, Sao Paulo, 2006. When a large compartment of a ship is flooded the water will affect the ship dynamic behaviour, and may have a significant impact on the vessel’s ability to withstand the action of waves. It is well known that complex dynamics can be associated with the loss of dynamic stability even for an intact ship, and these phenomena have been shown to be particularly relevant for fishing. We investigate here the effect of several levels of partial flooding on the dynamic processes that lead to loss of dynamic stability and capsize in waves. Two mathematical models are used in the present analysis. The first is a simplified model in which the vessel is acted upon by trains of regular beam waves. The free surface in this model is assumed to remain flat. The dynamic interaction between the vessel and the water inside it is modeled in such a way that the ensuing equations are those of a nonlinear inverted double pendulum. Drawing on this observation, an even simpler model was developed based on the idea of an equivalent mechanical pendulum. Since transient capsize in waves is a rapid phenomenon when compared to the flooding of a compartment, the analyses consider the percentage of flooding as a varying parameter.