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MARINE 2013 - Modeling of water flow with free surface of marine phenomena

Vth International Conference on Computational Methods in Marine Engineering

Hamburg 2013

Monika Warmowska
Polski Rejestr Statków S.A., Gdańsk
E-mail: rb@prs.pl


Modeling of water flow with free surface of marine phenomena

Modeling of irregular waves to simulate ship motion, sloshing inside ship tanks or flooded holds, flow of sea water over fishing vessels requires numerical methods that describe the phenomena of a deformed free surface. The paper presents the assumptions, algorithms and modelling results obtained.

Irregular waves are composed of regular waves, which are described as the oscillating of particles around their average position. The influence of existing free surface entails an additional component of Frouda-Krylov forces. The paper presents differences between the values of pressures obtained using linear and nonlinear methods.

The problem of sloshing (motion of water inside moving tank) was solved using two methods: Boundary Elements Method in case of tanks over 30% full and shallow water method in case of low liquid level in the tank. The changing of free surface in time domain cannot be omitted in either case. The results are compared to results obtained for an analytical solution for standing wave.

The shallow water problem is used to model the motion of seawater over a ship deck. The mass and volume of water dropped on deck keep changing during the simulation. The problem of free water entering and leaving the deck is modelled. The forces caused by water over the deck is presented.

The paper shows results of a few years of research performed in Polski Rejestr Statków to enhance ship safety. The studies contribute to better awareness of ship behaviour, capsizing phenomenon and crack of construction.